Annual report pursuant to Section 13 and 15(d)

Statements of Shareholders'/Members' Equity Statements of Shareholders/Members' Equity

v2.4.1.9
Statements of Shareholders'/Members' Equity Statements of Shareholders/Members' Equity (USD $)
In Thousands, except Share data
Total
USD ($)
Retained Earnings [Member]
USD ($)
Accumulated Other Comprehensive Income (Loss) [Member]
USD ($)
Restricted Stock [Member]
Common Stock [Member]
USD ($)
Restricted Stock Units (RSUs) [Member]
Performance Shares [Member]
Balance, beginning of period at Mar. 31, 2012 $ 192,480us-gaap_StockholdersEquity $ (2,910)us-gaap_StockholdersEquity
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_RetainedEarningsMember
$ 3,362us-gaap_StockholdersEquity
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedOtherComprehensiveIncomeMember
  $ 192,028us-gaap_StockholdersEquity
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
   
Common stock, shares outstanding, beginning of period at Mar. 31, 2012         30,208,084us-gaap_CommonStockSharesOutstanding
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
   
Net income (loss) 26,974us-gaap_NetIncomeLoss 26,974us-gaap_NetIncomeLoss
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_RetainedEarningsMember
         
Stock-based compensation expense 1,341us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue       1,341us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
   
Excess tax deduction from stock options 4,131us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities            
Net income (loss) 26,974us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic            
Foreign curency translation adjustment (4,133)us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent   (4,133)us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedOtherComprehensiveIncomeMember
       
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax 304us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax            
Foreign provision 12,352us-gaap_CurrentForeignTaxExpenseBenefit            
Other (304)us-gaap_AdjustmentsToAdditionalPaidInCapitalOther   (304)us-gaap_AdjustmentsToAdditionalPaidInCapitalOther
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedOtherComprehensiveIncomeMember
       
Issuance of common stock in exercise of stock options, shares         1,086,486us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
   
Issuance of common stock in exercise of stock options 5,558us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised       5,558us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
   
Issuance of restricted stock as deferred compensation to employees and directors       13,012us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_RestrictedStockMember
     
Excess tax deduction from stock options exercises 4,131us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation       4,131us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
   
Balance, end of period at Mar. 31, 2013 226,047us-gaap_StockholdersEquity 24,064us-gaap_StockholdersEquity
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_RetainedEarningsMember
(1,075)us-gaap_StockholdersEquity
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedOtherComprehensiveIncomeMember
  203,058us-gaap_StockholdersEquity
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
   
Common stock, shares outstanding, end of period at Mar. 31, 2013         31,307,582us-gaap_CommonStockSharesOutstanding
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
   
Net income (loss) 25,799us-gaap_NetIncomeLoss 25,799us-gaap_NetIncomeLoss
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_RetainedEarningsMember
         
Issuance of common stock in lieu of compensation, shares           18,786us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_RestrictedStockUnitsRSUMember
10,594us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PerformanceSharesMember
Stock-based compensation expense 2,203us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue       2,203us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
   
Excess tax deduction from stock options (118)us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities            
Net income (loss) 25,799us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic            
Foreign curency translation adjustment (6,724)us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent   (6,724)us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedOtherComprehensiveIncomeMember
       
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax 0us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax            
Foreign provision 12,451us-gaap_CurrentForeignTaxExpenseBenefit            
Other (81)us-gaap_AdjustmentsToAdditionalPaidInCapitalOther   (81)us-gaap_AdjustmentsToAdditionalPaidInCapitalOther
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedOtherComprehensiveIncomeMember
       
Issuance of common stock in exercise of stock options, shares         566,487us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
   
Issuance of common stock in exercise of stock options 3,340us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised       3,340us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
   
Issuance of restricted stock as deferred compensation to employees and directors       17,416us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_RestrictedStockMember
     
Excess tax deduction from stock options exercises (118)us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation       (118)us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
   
Balance, end of period at Mar. 31, 2014 250,466us-gaap_StockholdersEquity 49,863us-gaap_StockholdersEquity
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_RetainedEarningsMember
(7,880)us-gaap_StockholdersEquity
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedOtherComprehensiveIncomeMember
  208,483us-gaap_StockholdersEquity
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
   
Common stock, shares outstanding, end of period at Mar. 31, 2014 31,920,865us-gaap_CommonStockSharesOutstanding       31,920,865us-gaap_CommonStockSharesOutstanding
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
   
Issuance of common stock in lieu of compensation, shares         11,956us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
46,360us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_RestrictedStockUnitsRSUMember
15,162us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_PerformanceSharesMember
Stock-based compensation expense 3,295us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue       3,295us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
   
Excess tax deduction from stock options 1,592us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities            
Net income (loss) 49,386us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic            
Foreign curency translation adjustment (32,667)us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent   (32,667)us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedOtherComprehensiveIncomeMember
       
Interest rate swap (404)thr_OtherComprehensiveIncomeLossInterestRateSwapActivity   (404)thr_OtherComprehensiveIncomeLossInterestRateSwapActivity
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedOtherComprehensiveIncomeMember
       
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax 449us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax            
Foreign provision 13,160us-gaap_CurrentForeignTaxExpenseBenefit            
Other (449)us-gaap_AdjustmentsToAdditionalPaidInCapitalOther            
Issuance of common stock in exercise of stock options, shares         88,050us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
   
Issuance of common stock in exercise of stock options 547us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised            
Issuance of restricted stock as deferred compensation to employees and directors         11,956us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
   
Balance, end of period at Mar. 31, 2015 $ 271,766us-gaap_StockholdersEquity $ 99,249us-gaap_StockholdersEquity
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_RetainedEarningsMember
$ (41,400)us-gaap_StockholdersEquity
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedOtherComprehensiveIncomeMember
  $ 213,917us-gaap_StockholdersEquity
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
   
Common stock, shares outstanding, end of period at Mar. 31, 2015 32,082,393us-gaap_CommonStockSharesOutstanding       32,082,393us-gaap_CommonStockSharesOutstanding
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember