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 [Member] - USD ($)	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
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	$ 648,000	$ 627,000	$ 384,000
Options outstanding (in shares)	367,571.000	411,939.000	433,726	465,042
$5.20 [Member]
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)		238,863
Options outstanding, weighted average contractual life (in years)		2 years 6 months 18 days
Options outstanding, weighted average exercise price (in dollars per share)		$ 5.20
Options outstanding, aggregate intrinsic value		$ 4,110,832
Options vested and exercisable, number exercisable (in shares)		238,863
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term		2 years 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		$ 4,110,832
$9.82 [Member]
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)		2 years 10 months 28 days
Options outstanding, weighted average exercise price (in dollars per share)		$ 9.82
Options outstanding, aggregate intrinsic value		$ 167,938
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		2 years 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		$ 167,938
$12.00 [Member]
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)		47,250
Options outstanding, weighted average contractual life (in years)		3 years 1 month 2 days
Options outstanding, weighted average exercise price (in dollars per share)		$ 12.00
Options outstanding, aggregate intrinsic value		$ 491,248
Options vested and exercisable, number exercisable (in shares)		47,250
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term		3 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		$ 491,248
$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)		8 years 9 months 4 days
Options outstanding, weighted average exercise price (in dollars per share)		$ 19.64
Options outstanding, aggregate intrinsic value		$ 78,942
Options vested and exercisable, number exercisable (in shares)		9,499
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term		8 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		$ 26,312
$21.52 [Member]
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)		39,620
Options outstanding, weighted average contractual life (in years)		4 years 4 months 2 days
Options outstanding, weighted average exercise price (in dollars per share)		$ 21.52
Options outstanding, aggregate intrinsic value		$ 35,532
Options vested and exercisable, number exercisable (in shares)		39,620
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term		4 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		$ 35,532
$5.20 - $21.52 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options outstanding (in shares)		367,571
Options outstanding, weighted average contractual life (in years)		3 years 3 months 22 days
Options outstanding, weighted average exercise price (in dollars per share)		$ 9.12
Options outstanding, aggregate intrinsic value		$ 4,884,492
Options vested and exercisable, number exercisable (in shares)		348,571
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term		3 years 3 months 22 days
Options vested and exercisable, weighted average exercise price (in dollars per share)		8.55
Options vested and exercisable, aggregate intrinsic value		$ 4,831,862