Income Taxes - Schedule of Effective Tax Rates (Details)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. federal taxes at statutory rate	21.00%	21.00%	21.00%
State taxes, net of federal benefit	7.70%	7.50%	6.20%
Nondeductible expenses	0.50%	0.30%	0.40%
Stock compensation	2.80%	0.30%	0.20%
Foreign rate differential	(0.10%)	(0.20%)	(0.20%)
Federal and state credits	(4.70%)	(2.60%)	(3.20%)
CARES Act			(2.40%)
Disallowed officer compensation	0.80%	1.00%
Investment in partnership	1.00%	(0.30%)
Federal, state, and foreign provision to return differences	(0.80%)	(0.70%)
Uncertain tax provision	0.50%
Other	(0.00%)	(0.20%)	(0.20%)
Consolidated effective tax rate	28.70%	26.10%	21.80%
Effective tax rate attributable to redeemable noncontrolling interest	(1.00%)	0.20%
Effective tax rate attributable to CarGurus, Inc	27.70%	26.30%	21.80%