Leases - Lease cost and other information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Lease Cost Components:
Amortization of ROU assets - finance leases	$ 117	$ 117	$ 233	$ 233
Interest on lease liabilities - finance leases	12	14	25	29
Operating lease cost (cost resulting from lease payments)	4,536	4,342	8,869	8,685
Short-term lease cost	231	75	374	211
Variable lease cost (cost excluded from lease payments)	761	643	1,198	1,291
Total lease cost	5,657	5,191	10,699	10,449
Supplemental Cash Flow and Other Information Related to Leases:
Finance lease - operating cash flows	12	14	25	29
Finance lease - financing cash flows	108	106	216	213
Operating lease - operating cash flows (fixed payments)	4,444	4,173	8,626	8,313
Operating lease - operating cash flows (net change asset/liability)	(3,545)	$ (3,255)	(6,848)	(6,475)
New ROU assets - operating leases	$ 188		$ 12,616	$ 1,298
Weighted - average remaining lease term (years) - finance leases	5 years 11 months 1 day	6 years 10 months 28 days	5 years 11 months 1 day	6 years 10 months 28 days
Weighted - average remaining lease term (years) - Operating leases	10 years 1 month 9 days	11 years 1 month 20 days	10 years 1 month 9 days	11 years 1 month 20 days
Weighted - average discount rate - finance leases	1.70%	1.70%	1.70%	1.70%
Weighted - average discount rate - Operating leases	3.00%	3.30%	3.00%	3.30%
Maturity Analysis of Lease Liabilities:
2022 (excluding the six months ended June 30, 2022)	$ 8,648		$ 8,648
2023	16,718		16,718
2024	15,339		15,339
2025	13,912		13,912
2026	13,367		13,367
Thereafter	79,150		79,150
Total undiscounted cash flows	147,134		147,134
Discount on cash flows	(23,221)		(23,221)
Total operating lease liabilities	$ 123,913		$ 123,913		$ 115,900