Ameresco, Inc. Quarterly report pursuant to Section 13 or 15(d)

Leases - Additional Information (Details) $ in Thousands	3 Months Ended		9 Months Ended
Leases - Additional Information (Details) $ in Thousands	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($) project	Sep. 30, 2021 USD ($)
Lessee, Lease, Description [Line Items]
Commitment for future lease payments for leases that do not yet meet the criteria of a ROU asset or liability	$ 10,500		$ 10,500
Lease payments to be made over a period	20 years		20 years
Net amortization expense	$ 57	$ 57	$ (171)	$ (171)
Solar Photovoltaic Projects \| August 2018 Long Term Finance Liability
Lessee, Lease, Description [Line Items]
Solar PV projects sold \| project			3
Investment fund call option exercise			$ 9,751
Solar Photovoltaic Projects \| August 2018 Long Term Finance Liability \| Revolving Credit Facility \| Line of Credit
Lessee, Lease, Description [Line Items]
Available funding under lending commitment	218,817		$ 218,817
Solar Photovoltaic Projects \| December 2020 Long Term Finance Liability
Lessee, Lease, Description [Line Items]
Solar PV projects sold \| project			4
Investment fund call option exercise			$ 6,048
Solar Photovoltaic Projects \| December 2020 Long Term Finance Liability \| Revolving Credit Facility \| Line of Credit
Lessee, Lease, Description [Line Items]
Available funding under lending commitment	$ 9,890		$ 9,890