REVENUE - Summary of Contract Assets and Liabilities (Parenthetical) (Details) - USD ($) $ in Millions	12 Months Ended
Mar. 31, 2026	Mar. 31, 2025
Revenue from Contract with Customer [Abstract]
Sales type lease	$ 0.0	$ 0.4

Sales Type Lease Income Comprehensive Income Extensible List Not Disclosed Flag

No definition available.

Name:	oesx_SalesTypeLeaseIncomeComprehensiveIncomeExtensibleListNotDisclosedFlag
Namespace Prefix:	oesx_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration