Income taxes - Schedule of Significant Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Deferred tax assets:
Deferred compensation	$ 27,780	$ 27,161
Deferred rent and lease incentives	8,772	9,877
Net operating losses and credits	12,124	9,593
Receivable reserves	1,259	1,294
Accrued expenses	4,762	13,121
Auction rate securities reserves	62	1,394
Involuntary conversion	1,671	1,704
Other	981	958
Total deferred tax assets	57,411	65,102
Valuation allowance	(9,581)	(7,036)
Deferred tax assets after valuation allowance	47,830	58,066
Deferred tax liabilities:
Goodwill	40,984	41,775
Partnership investments	27,181	32,679
Company-owned life insurance	14,180	11,527
Depreciation	1,517	1,617
Other	303	272
Total deferred tax liabilities	84,165	87,870
Total deferred tax liabilities	$ (36,335)	$ (29,804)