Loans and Leases, Changes in Allowance for Credit Losses (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	$ 74,965	$ 66,885
Provision for/(recapture of) credit losses	0	7,750
Charge-offs	(10)	(60)
Recoveries	63	390
Net (charge-offs) / recoveries	53	330
Balance at end of period	75,018	74,965
Commercial & Agricultural R/E [Member]
Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	33,837	32,551
Provision for/(recapture of) credit losses	(46)	1,116
Charge-offs	0	0
Recoveries	0	170
Net (charge-offs) / recoveries	0	170
Balance at end of period	33,791	33,837
Construction [Member]
Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	4,432	3,026
Provision for/(recapture of) credit losses	184	1,406
Charge-offs	0	0
Recoveries	0	0
Net (charge-offs) / recoveries	0	0
Balance at end of period	4,616	4,432
Residential & Home Equity [Member]
Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	7,770	7,508
Provision for/(recapture of) credit losses	(57)	211
Charge-offs	0	(14)
Recoveries	8	65
Net (charge-offs) / recoveries	8	51
Balance at end of period	7,721	7,770
Commercial & Agricultural [Member]
Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	22,252	21,705
Provision for/(recapture of) credit losses	(419)	423
Charge-offs	0	0
Recoveries	18	124
Net (charge-offs) / recoveries	18	124
Balance at end of period	21,851	22,252
Commercial Leases [Member]
Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	6,537	1,924
Provision for/(recapture of) credit losses	386	4,613
Charge-offs	0	0
Recoveries	0	0
Net (charge-offs) / recoveries	0	0
Balance at end of period	6,923	6,537
Consumer and Other [Member]
Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	137	171
Provision for/(recapture of) credit losses	(48)	(19)
Charge-offs	(10)	(46)
Recoveries	37	31
Net (charge-offs) / recoveries	27	(15)
Balance at end of period	$ 116	$ 137