Annual report pursuant to Section 13 and 15(d)

Employee Benefits - (Details)

v3.19.2
Employee Benefits - (Details) - USD ($)
$ in Thousands
 12 Months Ended
Mar. 31, 2019
Mar. 31, 2018
Mar. 31, 2017
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]      
Annual vesting percentage 100.00%    
Employer matching contribution, percent 50.00%    
Maximum annual contribution per employee, percent 6.00%    
Employer discretionary contribution, amount $ 2,315 $ 2,119 $ 1,634
Incentive compensation paid 9,885 6,656 $ 2,324
Deferred compensation plan assets 1,557 574  
Deferred compensation liability 1,520 569  
Deferred compensation expense 21 51  
Unrealized gains (losses) (50) 36  
Thermon Europe B.V.      
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]      
Net benefit obligation   $ 1,840  
Pension Plan | Thermon Europe B.V.      
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]      
Postretirement healthcare obligation, net $ 2,185