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

Annual report pursuant to Section 13 and 15(d)

Debt and Financing Lease Liabilities - Energy Asset Financing Facilities and Term Loans (Details)

Debt and Financing Lease Liabilities - Energy Asset Financing Facilities and Term Loans (Details)							1 Months Ended	12 Months Ended
	Sep. 28, 2023 USD ($)	May 31, 2023 USD ($)	Mar. 31, 2023 USD ($)	Dec. 21, 2022 USD ($)	Oct. 31, 2022 USD ($)	Oct. 26, 2022 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Mar. 30, 2023 USD ($)	Mar. 28, 2023 USD ($) note	Jun. 30, 2022 USD ($) note	Mar. 31, 2022 USD ($)	Feb. 28, 2022 USD ($)
Debt Instrument [Line Items]
Repayments of long-term debt								$ 303,057,000	$ 161,857,000	$ 98,200,000
Settlement gain on undesignated derivatives								$ 694,000
Unamortized discount and debt issuance costs														$ 96,000
Interest rate swap instruments \| Designated as Hedging Instrument
Debt Instrument [Line Items]
Initial notional amount			$ 14,084,000								$ 14,084,000
Fixed Rate Due in June 2026 \| Loans Payable
Debt Instrument [Line Items]
Stated interest rate (percent)					6.50%
Maximum borrowing capacity					$ 125,000,000
Internal rate of return, percentage					8.25%
Agreement term					5 years
Proceeds from notes payable				$ 15,000,000		$ 80,000,000
Repayments of long-term debt						$ 26,530,000
Term Loan Due March 28, 2028 \| Secured Debt
Debt Instrument [Line Items]
Stated interest rate (percent)							7.21%	7.21%
Maximum borrowing capacity											14,084,000
Term Loan Due March 28, 2028 \| Term loan A
Debt Instrument [Line Items]
Maximum borrowing capacity											359,000
Term Loan Due March 28, 2028 \| Letter of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity											$ 899,000
Fixed Rate Note Payable in Quarterly Installments Due in March 2042 \| Loans Payable
Debt Instrument [Line Items]
Stated interest rate (percent)							5.45%	5.45%
Original principal amount													$ 7,113,000
Fixed Rate Note Payable in Quarterly Installments Due in March 2042 \| Senior Notes
Debt Instrument [Line Items]
Number of notes \| note													2
Term Shelf Notes Due December 31, 2047 \| Senior Notes
Debt Instrument [Line Items]
Stated interest rate (percent)												5.99%
Unamortized discount												$ 3,123,000
Debt issuance costs												$ 282,000
Number of notes \| note												3
Original principal amount												$ 22,625,000
Revolving Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity													$ 725,000,000
Revolving Credit Facility \| Line of Credit
Debt Instrument [Line Items]
Stated interest rate (percent)							9.54%	9.54%
Maximum borrowing capacity														200,000,000	$ 180,000,000
Unamortized discount														2,048,000
Debt issuance costs														$ 352,000
Revolving Credit Facility \| Fixed Rate Note, Due August, 2039 \| Line of Credit
Debt Instrument [Line Items]
Stated interest rate (percent)	6.70%	6.38%									6.50%
Maximum borrowing capacity	$ 500,000,000	$ 215,000,000	125,000,000
Internal rate of return, percentage							8.51%	8.51%
Net proceeds	$ 135,544,000	90,000,000	$ 30,000,000				$ 21,176,000
Line of credit facility, additional borrowing capacity		$ 90,000,000
Unamortized discount							509,000	$ 509,000
Debt issuance costs							305,000	305,000
Total maturities							348,020,000	348,020,000
Unamortized discount and debt issuance costs							$ 1,073,000	$ 1,073,000
Revolving Credit Facility \| Fixed Rate Note, Due August, 2039 \| Line of Credit \| Debt Covenant Period One
Debt Instrument [Line Items]
Internal rate of return prepayment percentage			102.00%
Revolving Credit Facility \| Fixed Rate Note, Due August, 2039 \| Line of Credit \| Debt Covenant Period Two
Debt Instrument [Line Items]
Internal rate of return prepayment percentage			101.00%