REVENUE FROM CONTRACTS WITH CUSTOMERS - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Disaggregation of Revenue [Line Items]
Revenues	$ 472,284	$ 437,982	$ 825,113	$ 736,388
Percentage of revenue recognized over time	96.00%	96.00%	96.00%	95.00%
United States
Disaggregation of Revenue [Line Items]
Revenues	$ 301,923	$ 349,500	$ 534,536	$ 588,599
Canada
Disaggregation of Revenue [Line Items]
Revenues	28,417	15,416	51,968	30,596
Europe
Disaggregation of Revenue [Line Items]
Revenues	141,944	73,066	238,609	117,193
Project revenue
Disaggregation of Revenue [Line Items]
Revenues	358,088	330,763	609,549	535,047
O&M revenue
Disaggregation of Revenue [Line Items]
Revenues	27,955	26,170	52,801	51,505
Energy assets
Disaggregation of Revenue [Line Items]
Revenues	62,909	53,416	119,602	96,570
Other
Disaggregation of Revenue [Line Items]
Revenues	23,332	27,633	43,161	53,266
North America Regions
Disaggregation of Revenue [Line Items]
Revenues	211,185	208,131	389,445	346,416
North America Regions \| Project revenue
Disaggregation of Revenue [Line Items]
Revenues	174,287	178,742	323,240	294,953
North America Regions \| O&M revenue
Disaggregation of Revenue [Line Items]
Revenues	10,474	8,511	18,930	15,444
North America Regions \| Energy assets
Disaggregation of Revenue [Line Items]
Revenues	22,669	19,746	41,639	33,500
North America Regions \| Other
Disaggregation of Revenue [Line Items]
Revenues	3,755	1,132	5,636	2,519
U.S. Federal
Disaggregation of Revenue [Line Items]
Revenues	59,644	86,737	84,891	147,627
U.S. Federal \| Project revenue
Disaggregation of Revenue [Line Items]
Revenues	37,459	68,080	43,497	111,559
U.S. Federal \| O&M revenue
Disaggregation of Revenue [Line Items]
Revenues	15,063	14,628	28,793	29,906
U.S. Federal \| Energy assets
Disaggregation of Revenue [Line Items]
Revenues	6,780	3,724	12,137	5,653
U.S. Federal \| Other
Disaggregation of Revenue [Line Items]
Revenues	342	305	464	509
Renewable Fuels
Disaggregation of Revenue [Line Items]
Revenues	42,819	45,852	80,994	78,711
Renewable Fuels \| Project revenue
Disaggregation of Revenue [Line Items]
Revenues	7,983	13,884	12,046	17,047
Renewable Fuels \| O&M revenue
Disaggregation of Revenue [Line Items]
Revenues	1,762	2,136	3,777	4,513
Renewable Fuels \| Energy assets
Disaggregation of Revenue [Line Items]
Revenues	33,071	29,728	65,168	57,028
Renewable Fuels \| Other
Disaggregation of Revenue [Line Items]
Revenues	3	104	3	123
Europe
Disaggregation of Revenue [Line Items]
Revenues	141,884	73,059	238,541	117,181
Europe \| Project revenue
Disaggregation of Revenue [Line Items]
Revenues	138,359	70,064	230,766	111,488
Europe \| O&M revenue
Disaggregation of Revenue [Line Items]
Revenues	656	895	1,301	1,642
Europe \| Energy assets
Disaggregation of Revenue [Line Items]
Revenues	389	189	658	360
Europe \| Other
Disaggregation of Revenue [Line Items]
Revenues	2,480	1,911	5,816	3,691
All Other
Disaggregation of Revenue [Line Items]
Revenues	16,752	24,203	31,242	46,453
All Other \| Project revenue
Disaggregation of Revenue [Line Items]
Revenues	0	(7)	0
All Other \| O&M revenue
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
All Other \| Energy assets
Disaggregation of Revenue [Line Items]
Revenues	0	29	0	29
All Other \| Other
Disaggregation of Revenue [Line Items]
Revenues	$ 16,752	$ 24,181	$ 31,242	$ 46,424

Ameresco, Inc. 10-Q