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

Fair Value Measurement - Fair Value of Assets and Liabilities Measured on a Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Liabilities:
Contingent consideration liabilities	$ 1,178
Recurring
Liabilities:
Total liabilities	7,832	$ 5,664
Recurring \| Fair Value, Inputs, Level 2
Assets:
Asset derivatives	213	766
Recurring \| Fair Value, Inputs, Level 2 \| Interest rate swap contracts
Assets:
Asset derivatives	15	733
Liabilities:
Liability derivatives	6,236	3,187
Recurring \| Fair Value, Inputs, Level 2 \| Commodity swap
Assets:
Asset derivatives	198	33
Liabilities:
Liability derivatives	0	70
Recurring \| Fair Value, Inputs, Level 2 \| Interest make-whole provisions
Liabilities:
Liability derivatives	918	1,808
Recurring \| Fair Value, Inputs, Level 3
Liabilities:
Contingent consideration liabilities	$ 678	$ 599