Quarterly report pursuant to Section 13 or 15(d)

Long-Term Debt (Details)

v2.4.0.6
Long-Term Debt (Details) (USD $)
3 Months Ended 6 Months Ended 12 Months Ended 3 Months Ended 6 Months Ended 12 Months Ended 6 Months Ended 12 Months Ended 3 Months Ended 6 Months Ended 3 Months Ended 6 Months Ended
Sep. 30, 2012
Sep. 30, 2011
Sep. 30, 2012
Sep. 30, 2011
Mar. 31, 2012
Sep. 30, 2012
Thermon Holding Corp.
Sep. 30, 2011
Thermon Holding Corp.
Sep. 30, 2012
Thermon Holding Corp.
Sep. 30, 2011
Thermon Holding Corp.
Mar. 31, 2012
Thermon Holding Corp.
Sep. 30, 2012
9.500% Senior Secured Notes, due May 2017
Sep. 30, 2011
9.500% Senior Secured Notes, due May 2017
Sep. 30, 2012
9.500% Senior Secured Notes, due May 2017
Thermon Holding Corp.
Sep. 30, 2011
9.500% Senior Secured Notes, due May 2017
Thermon Holding Corp.
Mar. 31, 2013
9.500% Senior Secured Notes, due May 2017
Thermon Holding Corp.
Sep. 30, 2012
Revolving credit facility
Sep. 30, 2012
Revolving credit facility
Sep. 30, 2012
Revolving credit facility
Thermon Holding Corp.
Sep. 30, 2012
Revolving credit facility
Thermon Holding Corp.
Sep. 30, 2012
Revolving credit facility
Thermon Industries, Inc.
Sep. 30, 2012
Revolving credit facility
Canadian subsidiary
Debt Instrument [Line Items]                                          
Interest rate (as a percent)                     9.50%   9.50%                
Long-term debt $ 118,145,000   $ 118,145,000   $ 139,145,000 $ 118,145,000   $ 118,145,000   $ 139,145,000 $ 118,145,000   $ 118,000,000                
Less current portion 0   0   (21,000,000) 0   0   (21,000,000)                      
Long-term debt, noncurrent 118,145,000   118,145,000   118,145,000 118,145,000   118,145,000   118,145,000                      
Maximum borrowing capacity                                       40,000,000 20,000,000
Borrowing base as a percentage of eligible accounts receivable                                 85.00%   85.00%    
Borrowing base as a percentage of eligible inventory                                 65.00%   65.00%    
Borrowing base as a percentage of net orderly liquidation value of eligible equipment                                 85.00%   85.00%    
Borrowing base as a percentage of fair market value of eligible owned real property                                 80.00%   80.00%    
Capacity available under credit facility                               39,205,000 39,205,000 39,205,000 39,205,000    
Outstanding borrowings           0   0                          
Interest rate at period end (as a percent)                               3.00% 3.00% 3.00% 3.00%    
Interest rate in addition to LIBOR rate                               2.50% 2.50% 2.50% 2.50%    
Annual commitment fee on unutilized commitments (as a percent)                                 0.40%   0.40%    
Cash interest expense 4,693,000 5,030,000 9,060,000 11,820,000   (4,693,000) (5,030,000) (9,060,000) (11,820,000)   11,224,000       11,000,000            
Partial redemptions     21,000,000 66,590,000       21,000,000 66,590,000   21,000,000 66,590,000 21,000,000 66,590,000              
Cash premiums paid on redemption               630,000 3,596,000   630,000 3,596,000 630,000 3,596,000              
Deferred debt amortization                     871,000 2,922,000   2,922,000   1,447,000   1,447,000      
Unrealized Gain (Loss) on Derivatives     106,000   188,000     106,000   188,000                      
Foreign Currency Transaction Risk                                          
Maximum term of forward contracts     90 days         90 days                          
Notional amounts of forward contracts held to sell U.S. dollars in exchange for other major international currencies 22,938,000   22,938,000   14,429,000 22,938,000   22,938,000   14,429,000                      
Net foreign exchange transaction losses $ 8,000 $ 1,151,000 $ 61,000 $ 1,242,000   $ 8,000 $ 1,151,000 $ 61,000 $ 1,242,000