Leases - Lease cost and other information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Lease Cost Components:
Amortization of ROU assets - finance leases	$ 117	$ 117	$ 350	$ 350
Interest on lease liabilities - finance leases	8	10	26	31
Operating lease cost (cost resulting from lease payments)	4,025	4,296	12,658	12,814
Short-term lease cost	144	104	467	318
Variable lease cost (cost excluded from lease payments)	704	852	2,457	2,327
Total lease cost	4,998	5,379	15,958	15,840
Supplemental Cash Flow and Other Information Related to Leases:
Finance lease - operating cash flows	8	10	26	31
Finance lease - financing cash flows	120	111	357	331
Operating lease - operating cash flows (fixed payments)	4,450	4,233	12,862	12,483
Operating lease - operating cash flows (net change asset/liability)	$ (3,436)	$ (3,400)	(10,103)	(10,008)
New ROU assets - operating leases			$ 9,093	$ 701
Weighted - average remaining lease term (years) - finance leases	3 years 8 months 8 days	4 years 8 months 4 days	3 years 8 months 8 days	4 years 8 months 4 days
Weighted - average remaining lease term (years) - operating leases	8 years 7 months 17 days	9 years 5 months 19 days	8 years 7 months 17 days	9 years 5 months 19 days
Weighted - average discount rate - finance leases	1.70%	1.70%	1.70%	1.70%
Weighted - average discount rate - operating leases	3.40%	3.10%	3.40%	3.10%
Maturity Analysis of Lease Liabilities:
2024 (excluding 9 months ended September 30, 2024)	$ 4,300		$ 4,300
2025	16,467		16,467
2026	15,964		15,964
2027	14,797		14,797
2028	14,138		14,138
Thereafter	61,258		61,258
Total undiscounted cash flows	126,924		126,924
Discount on cash flows	(18,392)		(18,392)
Total operating lease liabilities	$ 108,532		$ 108,532		$ 108,300
Operating Lease, Liability, Statement of Financial Position [Extensible List]	Other Liabilities.		Other Liabilities.		Other Liabilities.