Income taxes - Schedule of Reconciliation of Effective Income Tax Rate (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Amount
U.S. federal statutory income tax	$ 44,344	$ 22,194	$ 9,806
U.S. state and local income taxes, net of U.S. federal income tax benefits	12,351	7,062	1,805
Other	(28)	147	315
Executive compensation	4,910	2,747	1,514
Meals and entertainment expenses	974	853	726
Fine and penalties	0	364	2,859
Transit and parking expenses	505	492	501
Insurance proceeds	(664)	(885)	(511)
Interest income	(222)	(209)	(453)
Other	74	68	28
Excess tax benefits from share-based awards	(1,547)	(671)	(1,317)
Total income taxes	$ 63,232	$ 34,510	$ 16,498
Percentage
U.S. federal statutory income tax	21.00%	21.00%	21.00%
U.S. state and local income taxes, net of U.S. federal income tax benefits (as a percent)	5.80%	6.60%	3.90%
Other	0.00%	0.10%	0.70%
Executive compensation	2.40%	2.60%	3.20%
Meals and entertainment expenses	0.50%	0.80%	1.60%
Fine and penalties	0.00%	0.30%	6.10%
Transit and parking expenses	0.20%	0.50%	1.10%
Insurance proceeds	(0.30%)	(0.80%)	(1.10%)
Interest income	(0.10%)	(0.20%)	(1.00%)
Other	0.00%	0.10%	(0.10%)
Excess tax benefits from share-based awards	(0.70%)	(0.60%)	(2.80%)
Total income taxes	29.90%	32.60%	35.30%
United Kingdom
Amount
Changes in valuation allowances	$ 2,638	$ 1,869	$ 1,945
Foreign tax effects	(500)	(370)	(203)
Other	$ 102	$ 592	$ (358)
Percentage
Changes in valuation allowances	1.20%	1.80%	4.20%
Foreign tax effects	(0.20%)	(0.30%)	(0.40%)
Other	0.00%	0.50%	(0.80%)
Other foreign jurisdictions
Amount
Foreign tax effects	$ 295	$ 257	$ (159)
Percentage
Foreign tax effects	0.10%	0.20%	(0.30%)