Thermon Group Holdings, Inc. Annual report [Section 13 and 15(d), not S-K Item 405]

Commitments and Contingencies - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2026	Mar. 31, 2025	Mar. 31, 2024
Long-Term Purchase Commitment [Line Items]
Borrowings under revolving credit facility	$ 19,700	$ 0
Guarantee obligations represented by a reduction of the available amount of the company's short term and long term revolving lines of credit	1,013	2,108
Merger and acquisition advisory fees	33,136
Service fee expense	5,075	4,857	$ 4,018
Performance Bonds \| Line of Credit
Long-Term Purchase Commitment [Line Items]
Borrowings under revolving credit facility	5,657	5,307
Letter of Credit \| Line of Credit \| Customers
Long-Term Purchase Commitment [Line Items]
Borrowings under revolving credit facility	5,751	7,867
Letters Of Credit, Cash Secured Bank Guarantees \| Line of Credit \| Customers
Long-Term Purchase Commitment [Line Items]
Borrowings under revolving credit facility	1,417	789
Letter of Credit, No Borrowing Capacity Impact \| Line of Credit
Long-Term Purchase Commitment [Line Items]
Borrowings under revolving credit facility	3,322	4,670
Letters of Credit and Performance Bonds \| Line of Credit
Long-Term Purchase Commitment [Line Items]
Borrowings under revolving credit facility	11,408	13,174
Custom Bonds \| Line of Credit \| Affiliated Entity
Long-Term Purchase Commitment [Line Items]
Borrowings under revolving credit facility	$ 3,866	$ 4,247