Quarterly report pursuant to Section 13 or 15(d)

Long-Term Debt (Details)

v3.20.2
Long-Term Debt (Details)
$ in Thousands
 6 Months Ended 9 Months Ended
Dec. 31, 2020
Jun. 18, 2020
USD ($)
Oct. 30, 2017
USD ($)
Oct. 30, 2017
CAD ($)
Sep. 30, 2020
USD ($)
Sep. 30, 2019
USD ($)
Sep. 30, 2020
USD ($)
Mar. 31, 2020
USD ($)
Apr. 01, 2018
Mar. 31, 2017
USD ($)
Debt Instrument [Line Items]                    
Less current portion         $ (2,500,000)   $ (2,500,000) $ (2,500,000)    
Long-term debt, net of current maturities and deferred debt issuance costs and debt discounts of $3,962 and $4,447 as of September 30, 2020 and March 31, 2020, respectively         168,288,000   168,288,000 169,053,000    
Debt issuance costs, net         3,962,000   3,962,000 4,447,000    
Repayments of long-term debt         38,714,000 $ 23,131,000        
Maximum leverage ratio to secure additional borrowing     4.0 4.0            
Amount of excess cash   $ 20,000                
Loans Payable                    
Debt Instrument [Line Items]                    
Debt Instrument, face amount                   $ 5,905,000
Revolving credit facility                    
Debt Instrument [Line Items]                    
Capacity available under credit facility         55,435,000   $ 55,435,000      
Through March 31, 2019 | Loans Payable                    
Debt Instrument [Line Items]                    
Repayments of notes payable         $ 625          
Revolving credit facility | Line of Credit                    
Debt Instrument [Line Items]                    
Debt Instrument, face amount     $ 60,000,000              
Long-term Debt, Term     5 years              
Repayments of lines of credit     $ 6,000,000              
Liabilities incurred       $ 201,900            
Line of credit facility, commitment fee percentage     0.50% 0.50%            
Maximum leverage ratio             4.5      
Debt covenant, coverage ratio     1.25 1.25            
Revolving credit facility | Base Rate | Line of Credit                    
Debt Instrument [Line Items]                    
Basis spread on variable rate     2.25% 2.25%            
Revolving credit facility | London Interbank Offered Rate (LIBOR) | Line of Credit                    
Debt Instrument [Line Items]                    
Basis spread on variable rate     3.25% 3.25%            
Revolving credit facility | Canadian Base Rate [Member] | Line of Credit                    
Debt Instrument [Line Items]                    
Basis spread on variable rate     2.25% 2.25%            
Revolving credit facility | CDOR | Line of Credit                    
Debt Instrument [Line Items]                    
Basis spread on variable rate     3.25% 3.25%            
Variable Rate Term Loan due October 2024                    
Debt Instrument [Line Items]                    
Variable term loan, interest rate         4.75%   4.75%      
Variable Rate Term Loan due October 2024 | Loans Payable                    
Debt Instrument [Line Items]                    
Variable Rate Term Loans         $ 170,788,000   $ 170,788,000 171,553,000    
Debt issuance costs, net         $ 3,962,000   $ 3,962,000 $ 4,447,000    
Variable Rate Senior Secured Term Loan B | Secured Debt                    
Debt Instrument [Line Items]                    
Debt Instrument, face amount     $ 250,000,000              
Long-term Debt, Term     7 years              
Variable interest rate floor     1.00%              
Quarterly amortization of debt, percent                 0.25%  
Repayment requirement, percentage of excess cash flow         50.00%          
Reduced repayment requirement, percentage of excess cash flow         25.00%          
Maximum leverage ratio requirement for reduced payment         4.0          
Minimum leverage ratio requirement for reduced payment         3.5          
Minimum repayment requirement percentage of excess cash flow         0.00%          
Maximum leverage ratio requirement for minimum repayment         3.5          
Maximum leverage ratio         3.5          
Additional borrowing capacity     $ 30,000,000              
Variable Rate Senior Secured Term Loan B | Secured Debt | Subsidiary Stock                    
Debt Instrument [Line Items]                    
Guarantor obligations, percentage     100.00% 100.00%            
Variable Rate Senior Secured Term Loan B | Secured Debt | Stock of First Tier Material Foreign Subsidiaries, US Borrower, and US Subsidiary                    
Debt Instrument [Line Items]                    
Guarantor obligations, percentage     65.00% 65.00%            
Variable Rate Senior Secured Term Loan B | Base Rate | Secured Debt                    
Debt Instrument [Line Items]                    
Basis spread on variable rate     2.75% 2.75%            
Variable Rate Senior Secured Term Loan B | London Interbank Offered Rate (LIBOR) | Secured Debt                    
Debt Instrument [Line Items]                    
Basis spread on variable rate     3.75% 3.75%            
Term Loan A due April 2019                    
Debt Instrument [Line Items]                    
Repayments of long-term debt     $ 70,875,000              
Thermon Heating Systems Inc.                    
Debt Instrument [Line Items]                    
Debt proceeds used as consideration for business acquisition     $ 164,900,000              
Scenario, Forecast | Revolving credit facility | Line of Credit                    
Debt Instrument [Line Items]                    
Maximum leverage ratio 3.75