Operating Leases - Operating lease income and expense and other supplemental information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating lease income and expense
Operating lease cost	$ 8,186	$ 6,449	$ 5,067
Variable lease cost	1,066	757	449
Short-term lease cost	85	100	136
Total lease cost	9,337	7,306	5,652
Sublease income and rental income from owned properties under operating leases	$ 976	$ 1,022	$ 1,160
Operating lease, weighted average remaining lease term (in years)	5 years 4 months 24 days	5 years 8 months 26 days	5 years 3 months 29 days
Operating lease, weighted average discount rate (percent)	1.58%	1.79%	2.79%