Annual report pursuant to Section 13 and 15(d)

Long-Term Debt (Details)

v3.4.0.3
Long-Term Debt (Details)
12 Months Ended
Jun. 11, 2014
May. 20, 2013
USD ($)
Mar. 31, 2016
USD ($)
Mar. 31, 2015
USD ($)
Mar. 31, 2014
USD ($)
Dec. 31, 2015
USD ($)
Apr. 30, 2013
USD ($)
Debt Instrument [Line Items]              
Debt instrument, maturity date     Apr. 30, 2019        
Less current portion     $ (13,500,000) $ (13,500,000)      
Long-term debt, noncurrent     80,112,000 93,283,000      
Debt issuance costs, net     $ 888,000 1,217,000      
Debt Instrument, Interest Rate, Increase (Decrease)     (0.25%)        
Line of Credit Facility, Commitment Fee Percentage, Increase (Decrease) (0.05%)            
Premium paid on redemption of senior secured notes     $ 0 0 $ (15,485,000)    
Secured Debt [Member]              
Debt Instrument [Line Items]              
Debt instrument, face amount             $ 135,000,000,000
Loans Payable [Member]              
Debt Instrument [Line Items]              
Interest rate (as a percent)     2.44%        
Long-term debt     $ 93,612,000 106,783,000      
Senior secured note [Member]              
Debt Instrument [Line Items]              
Repayments of Notes Payable   $ 118,145,000          
Premium paid on redemption of senior secured notes   15,485,000          
Write off of Deferred Debt Issuance Cost   $ 4,010,000          
Revolving Credit Facility [Member]              
Debt Instrument [Line Items]              
Debt Instrument, Fee     .00125        
Maximum leverage ratio 2.75            
Capacity available under credit facility     $ 59,022,000        
Outstanding borrowings           $ 0  
Annual commitment fee on unutilized commitments (as a percent)     0.30%        
Revolving Credit Facility [Member] | Thermon Industries, Inc. [Member]              
Debt Instrument [Line Items]              
Interest rate at period end (as a percent)     2.44%        
Period One [Member] | Loans Payable [Member]              
Debt Instrument [Line Items]              
Repayments of Notes Payable     $ 1,125,000        
Period Two [Member] | Loans Payable [Member]              
Debt Instrument [Line Items]              
Repayments of Notes Payable     1,688,000        
Period Three [Member] | Loans Payable [Member]              
Debt Instrument [Line Items]              
Repayments of Notes Payable     40,500,000        
Revolving Credit Facility [Member]              
Debt Instrument [Line Items]              
Outstanding borrowings     $ 0 $ 0      
Revolving Credit Facility [Member] | Line of Credit [Member]              
Debt Instrument [Line Items]              
Debt instrument, face amount             $ 60,000,000,000
Minimum [Member]              
Debt Instrument [Line Items]              
Derivative, Fixed Interest Rate     3.12%        
Maximum [Member]              
Debt Instrument [Line Items]              
Derivative, Fixed Interest Rate     3.81%