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

Annual report pursuant to Section 13 and 15(d)

Stock-Based Compensation Expense - Stock Options Outstanding, Exercisable and Intrinsic Value (Details)

Stock-Based Compensation Expense - Stock Options Outstanding, Exercisable and Intrinsic Value (Details) - Stock Options - USD ($)	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value	$ 555,000	$ 648,000	$ 627,000
Options outstanding (in shares)	329,386.000	367,571.000	411,939	433,726
$5.20
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Exercise Price	$ 5.20
Options outstanding (in shares)	216,952
Options outstanding, weighted average contractual life (in years)	1 year 6 months 18 days
Options outstanding, weighted average exercise price (in dollars per share)	$ 5.20
Options outstanding, aggregate intrinsic value	$ 4,189,343
Options vested and exercisable, number exercisable (in shares)	216,952
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term	1 year 6 months 18 days
Options vested and exercisable, weighted average exercise price (in dollars per share)	5.20
Options vested and exercisable, aggregate intrinsic value	$ 4,189,343
$9.82
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Exercise Price	$ 9.82
Options outstanding (in shares)	13,339
Options outstanding, weighted average contractual life (in years)	1 year 10 months 28 days
Options outstanding, weighted average exercise price (in dollars per share)	$ 9.82
Options outstanding, aggregate intrinsic value	$ 195,950
Options vested and exercisable, number exercisable (in shares)	13,339
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term	1 year 10 months 28 days
Options vested and exercisable, weighted average exercise price (in dollars per share)	9.82
Options vested and exercisable, aggregate intrinsic value	$ 195,950
$12.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Exercise Price	$ 12.00
Options outstanding (in shares)	40,690
Options outstanding, weighted average contractual life (in years)	2 years 1 month 2 days
Options outstanding, weighted average exercise price (in dollars per share)	$ 12.00
Options outstanding, aggregate intrinsic value	$ 508,407
Options vested and exercisable, number exercisable (in shares)	40,690
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term	2 years 1 month 2 days
Options vested and exercisable, weighted average exercise price (in dollars per share)	12.00
Options vested and exercisable, aggregate intrinsic value	$ 508,407
$19.64
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Exercise Price	$ 19.64
Options outstanding (in shares)	28,499
Options outstanding, weighted average contractual life (in years)	7 years 9 months 4 days
Options outstanding, weighted average exercise price (in dollars per share)	$ 19.64
Options outstanding, aggregate intrinsic value	$ 138,790
Options vested and exercisable, number exercisable (in shares)	18,999
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term	7 years 9 months 4 days
Options vested and exercisable, weighted average exercise price (in dollars per share)	19.64
Options vested and exercisable, aggregate intrinsic value	$ 92,525
$21.52
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Exercise Price	$ 21.52
Options outstanding (in shares)	29,906
Options outstanding, weighted average contractual life (in years)	3 years 4 months 2 days
Options outstanding, weighted average exercise price (in dollars per share)	$ 21.52
Options outstanding, aggregate intrinsic value	$ 89,689
Options vested and exercisable, number exercisable (in shares)	29,906
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term	3 years 4 months 2 days
Options vested and exercisable, weighted average exercise price (in dollars per share)	21.52
Options vested and exercisable, aggregate intrinsic value	$ 89,689
$5.20 - $21.52
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options outstanding (in shares)	329,386
Options outstanding, weighted average contractual life (in years)	2 years 3 months 28 days
Options outstanding, weighted average exercise price (in dollars per share)	$ 8.96
Options outstanding, aggregate intrinsic value	$ 5,122,179
Options vested and exercisable, number exercisable (in shares)	319,886
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term	2 years 1 month 30 days
Options vested and exercisable, weighted average exercise price (in dollars per share)	8.64
Options vested and exercisable, aggregate intrinsic value	$ 5,075,914
Minimum
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Exercise Price	$ 5.20
Maximum
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Exercise Price	$ 21.52