Thermon Group Holdings, Inc. Quarterly report pursuant to Section 13 or 15(d)

Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation Expense (Details)

Stock-Based Compensation Expense (Details) $ in Thousands	3 Months Ended		9 Months Ended		49 Months Ended
Stock-Based Compensation Expense (Details) $ in Thousands	Dec. 31, 2018 USD ($) shares	Dec. 31, 2017 USD ($)	Dec. 31, 2018 USD ($) shares	Dec. 31, 2017 USD ($)	Jun. 30, 2014 plan	Apr. 08, 2011 shares	Jul. 28, 2010 shares
Stock-Based Compensation Expense
Number of stock option award plans \| plan					2
Options outstanding (in shares)	344,487		344,487
Stock compensation expense \| $	$ 1,041	$ 895	$ 3,130	$ 2,627
Restricted Stock and Stock Option Plan
Stock-Based Compensation Expense
Maximum number of shares of the company's common stock that may be awarded							2,767,171
2011 Long-term Incentive Plan
Stock-Based Compensation Expense
Maximum number of shares of the company's common stock that may be awarded						2,893,341
Restricted Stock Units
Stock-Based Compensation Expense
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period			89,114
Stock Issued During Period, Value, Restricted Stock Award, Gross \| $			$ 2,098
Share-based Compensation Arrangement by Share-based Payment Award, Award Requisite Service Period			3 years
Common Stock
Stock-Based Compensation Expense
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	4,516		14,968
Stock Issued During Period, Value, Restricted Stock Award, Gross \| $	$ 115		$ 350
Share-based compensation arrangement by share-based payment award, fair value of shares authorized amount \| $	$ 420		$ 420
Performance Shares
Stock-Based Compensation Expense
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period			11,533
Stock Issued During Period, Value, Restricted Stock Award, Gross \| $			$ 320
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Fair Value \| $			$ 0
Minimum
Stock-Based Compensation Expense
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Possible Number of Performance Shares to be Granted			0
Maximum
Stock-Based Compensation Expense
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Possible Number of Performance Shares to be Granted			23,066
Management \| Performance Shares
Stock-Based Compensation Expense
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period			46,032
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period			3 years
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Fair Value \| $			$ 1,084
Management \| Minimum
Stock-Based Compensation Expense
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Possible Number of Performance Shares to be Granted			0
Management \| Maximum
Stock-Based Compensation Expense
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Possible Number of Performance Shares to be Granted			15,920
Management \| Maximum \| Performance Shares
Stock-Based Compensation Expense
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Possible Number of Performance Shares to be Granted			92,064
Executive Officer \| Performance Shares
Stock-Based Compensation Expense
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	10,613