Allowance for Credit Losses on Loans (Allowance for Loan Losses Rollforward Analysis) (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance, Beginning Balance	$ 41,057	$ 38,027	$ 38,027
Charge-offs	(70)	(61)	(577)
Recoveries	18	14
Provision	900	800
Allowance, Ending Balance	41,905	38,780	41,057
Commercial Real Estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance, Beginning Balance	24,144	18,435	18,435
Charge-offs	0	0	(373)
Recoveries	0	0
Provision	712	2,939
Allowance, Ending Balance	24,856	21,374	24,144
Commercial & Industrial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance, Beginning Balance	8,088	10,356	10,356
Charge-offs	(8)	(11)	(37)
Recoveries	9	5
Provision	(469)	(517)
Allowance, Ending Balance	7,620	9,833	8,088
Total Commercial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance, Beginning Balance	32,232	28,791	28,791
Charge-offs	(8)	(11)
Recoveries	9	5
Provision	243	2,422
Allowance, Ending Balance	32,476	31,207	32,232
Residential Real Estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance, Beginning Balance	7,403	7,740	7,740
Charge-offs	0	0	0
Recoveries	0	0
Provision	632	(1,501)
Allowance, Ending Balance	8,035	6,239	7,403
Home Equity
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance, Beginning Balance	1,048	1,115	1,115
Charge-offs	0	0	0
Recoveries	1	1
Provision	8	(138)
Allowance, Ending Balance	1,057	978	1,048
Other
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance, Beginning Balance	374	381	381
Charge-offs	(62)	(50)	(167)
Recoveries	8	8
Provision	17	17
Allowance, Ending Balance	337	356	374
Total Consumer
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance, Beginning Balance	1,422	1,496	1,496
Charge-offs	(62)	(50)
Recoveries	9	9
Provision	25	(121)
Allowance, Ending Balance	$ 1,394	$ 1,334	$ 1,422