Income taxes - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Schedule Of Income Taxes [Line Items]
Income (loss) before income taxes for foreign operations	$ 7,700	$ 1,200	$ 1,500
Effective income tax (as a percent)	29.50%	29.20%	27.20%
Valuation allowance	$ 7,036	$ 6,153
Goodwill amortized period		15 years
Unrecognized tax benefits	1,072	$ 343	$ 212	$ 1,079
Net change in total valuation allowance	1,000
Additions for tax positions of prior years	729	343	212
Unrecognized tax benefit that would impact tax rate	847	271
Unrecognized tax benefits, penalties and interest tax expense	173	164	$ 227
Income tax-related interest payable	214	$ 41
State and Local Jurisdiction
Schedule Of Income Taxes [Line Items]
Unrecognized tax benefits	700
Oppenheimer Israel (OPCO) Ltd.
Schedule Of Income Taxes [Line Items]
Net operating loss carryforward	2,400
Oppenheimer Europe Ltd
Schedule Of Income Taxes [Line Items]
Valuation allowance	$ 5,400