Ameresco, Inc. Annual report pursuant to Section 13 and 15(d)

Annual report pursuant to Section 13 and 15(d)

Energy Assets - Additional Information (Details)

Energy Assets - Additional Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) developer project	Dec. 31, 2018 USD ($) developer project	Dec. 31, 2017 USD ($)	Jan. 01, 2019 USD ($)
Property, Plant and Equipment [Line Items]
Energy assets, net	$ 579,461	$ 459,952
Financing lease assets	42,402	42,402
Less - accumulated depreciation and amortization	(6,268)	(4,139)
Financing lease assets, net	36,134	38,263		$ 38,263
Project asset depreciation	35,543	27,305	$ 21,648
Depreciation and amortization expense on capital lease assets	2,129	2,090	1,305
Interest costs capitalized	$ 2,966	$ 3,817	4,256
Number of ESPC asset projects \| project	3	3
Contract with customer, liability	$ 32,178	$ 30,706
Contract with customer, current liability	$ 26,618	$ 24,363
Number of projects acquired \| project	10
Number of developers current year solar projects were purchased from \| developer	2	2
Fair value of consideration	$ 13,902
Contingent consideration liabilities	1,178
Payments to acquire businesses		$ 366
Asset retirement obligation, project assets	852	897
Asset retirement obligation	941	897
Depreciation	2,987	2,167	$ 2,394
Accretion expense	44	0
Renewal Energy Program
Property, Plant and Equipment [Line Items]
Energy assets	767,331	619,707
Less - accumulated depreciation and amortization	(187,870)	(159,756)
Energy assets, net	579,461	459,951
Contract with customer, liability	$ 10,243	9,863
Solar Projects 2019
Property, Plant and Equipment [Line Items]
Number of projects acquired \| project	9
Number of developers current year solar projects were purchased from \| developer	2
Fair value of consideration	$ 8,519
Contingent consideration liabilities	$ 6,059
Payments to acquire businesses		$ 2,460
Solar Projects 2018
Property, Plant and Equipment [Line Items]
Number of projects acquired \| project	9	12
Number of developers current year solar projects were purchased from \| developer		2
Fair value of consideration		$ 72,921
Contingent consideration liabilities		5,437
Payments to acquire businesses		62,116
Accrued Expenses And Other Current Liabilities \| Renewal Energy Program
Property, Plant and Equipment [Line Items]
Contract with customer, current liability	$ 827	354
Asset Retirement Obligation (ARO) Asset
Property, Plant and Equipment [Line Items]
Depreciation	$ 45	$ 0