Thermon Group Holdings, Inc. Annual report pursuant to Section 13 and 15(d)

Fair Value Measurements - Foreign Exchange Contracts by Currency (Details) (Foreign Exchange Forward Contracts [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Derivatives [Line Items]
Gain (Loss) on Foreign Currency Derivatives Recorded in Earnings, Net	$ (559)	$ (309)	$ 3
Notional amount	8,223invest_DerivativeNotionalAmount	8,178invest_DerivativeNotionalAmount
Russian Rubles [Member]
Derivatives [Line Items]
Notional amount	1,374	772
Euro [Member]
Derivatives [Line Items]
Notional amount	467	2,386
Canada, Dollars
Derivatives [Line Items]
Notional amount	243	0
South Korean Won [Member]
Derivatives [Line Items]
Notional amount	3,347	532
India, Rupees
Derivatives [Line Items]
Notional amount	0	2,574
Mexico, Pesos
Derivatives [Line Items]
Notional amount	873	1,077
Australia, Dollars
Derivatives [Line Items]
Notional amount	1,104	147
Japan, Yen
Derivatives [Line Items]
Notional amount	815	296
United Kingdom, Pounds
Derivatives [Line Items]
Notional amount	0	202
China, Yuan Renminbi
Derivatives [Line Items]
Notional amount	$ 0	$ 192