Quarterly report pursuant to Section 13 or 15(d)

Long-Term Debt (Details)

v3.19.2
Long-Term Debt (Details)
$ in Thousands
3 Months Ended 9 Months Ended 12 Months Ended
Dec. 31, 2020
Oct. 30, 2017
CAD ($)
Oct. 30, 2017
USD ($)
Jun. 30, 2019
USD ($)
Jun. 30, 2018
USD ($)
Sep. 30, 2020
Sep. 30, 2019
Sep. 30, 2018
Mar. 31, 2019
USD ($)
Apr. 01, 2018
Debt Instrument [Line Items]                    
Less current portion       $ (2,500,000)         $ (2,500,000)  
Long-term debt, net of current maturities and deferred debt issuance costs and debt discounts of $5,991 and $6,271 as of June 30, 2019 and March 31, 2019, respectively       197,384,000         197,729,000  
Debt issuance costs       7,263,000         7,967,000  
Debt issuance costs, net       5,991,000         6,271,000  
Repayments of long-term debt       7,494,000 $ 4,625,000          
Maximum leverage ratio to secure additional borrowing   4.0 4.0              
Outstanding borrowings       14,551,000         11,225,000  
Loans Payable                    
Debt Instrument [Line Items]                    
Debt Instrument, face amount                 5,905,000  
Revolving credit facility                    
Debt Instrument [Line Items]                    
Outstanding borrowings       14,551,000            
Capacity available under credit facility       41,390,000            
Through March 31, 2019 | Loans Payable                    
Debt Instrument [Line Items]                    
Repayments of notes payable       625            
Revolving credit facility                    
Debt Instrument [Line Items]                    
Outstanding borrowings                 0  
Revolving credit facility | Line of Credit                    
Debt Instrument [Line Items]                    
Debt Instrument, face amount     $ 60,000,000              
Repayments of lines of credit     $ 6,000,000              
Business Combination, Consideration Transferred, Liabilities Incurred   $ 201,900                
Line of credit facility, commitment fee percentage   0.50% 0.50%              
Maximum leverage ratio               5.5    
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 | Loans Payable                    
Debt Instrument [Line Items]                    
Variable Rate Term Loans       199,884,000         $ 200,229,000  
Debt issuance costs, net       9,089,000            
Variable Rate Term Loan due April 2019 | Loans Payable                    
Debt Instrument [Line Items]                    
Debt issuance costs, net       $ 524,000            
Variable Rate Senior Secured Term Loan B | Secured Debt                    
Debt Instrument [Line Items]                    
Debt Instrument, face amount     $ 250,000,000              
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%            
Additional borrowing capacity     $ 30,000,000              
Debt Instrument, Debt Covenant, Maximum Leverage Ratio Requirement For Reduced Repayment                 4.0  
Debt Instrument, Debt Covenant, Minimum Leverage Ratio Requirement For Reduced Repayment                 3.5  
Debt Instrument, Debt Covenant, Minimum Repayment Requirement, Percentage of Excess Cash Flow                 0.00%  
Debt Instrument, Debt Covenant, Maximum Leverage Ratio Requirement For Minimum Repayment                 3.5  
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 [Member] | Revolving credit facility | Line of Credit                    
Debt Instrument [Line Items]                    
Maximum leverage ratio 3.75         4.5 5.0      
US Borrower | Revolving credit facility                    
Debt Instrument [Line Items]                    
Interest rate at period end (as a percent)       4.93%            
Canadian Borrower | Revolving credit facility                    
Debt Instrument [Line Items]                    
Interest rate at period end (as a percent)       4.56%