Ameresco, Inc. Quarterly report [Sections 13 or 15(d)]

DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES - Fair Value of Derivative Instruments on the Balance Sheet (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Derivatives Designated as Hedging Instruments \| Interest rate swap contracts \| Other assets
Derivatives, Fair Value [Line Items]
Asset derivatives	$ 792	$ 721
Derivatives Not Designated as Hedging Instruments \| Interest rate swap contracts \| Accrued expenses and other current liabilities
Derivatives, Fair Value [Line Items]
Liability derivatives	37	0
Derivatives Not Designated as Hedging Instruments \| Interest rate swap contracts \| Other liabilities
Derivatives, Fair Value [Line Items]
Liability derivatives	0	197
Derivatives Not Designated as Hedging Instruments \| Make-whole provisions \| Other liabilities
Derivatives, Fair Value [Line Items]
Liability derivatives	$ 21,025	$ 19,075