Loans And Allowance For Credit Losses (Summary of Activity in the Allowance for Credit Losses) (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 for Credit Loss, Beginning Balance	$ 162,395	$ 150,136	$ 150,136
Provision for credit losses on loans	6,947	15,948
Loans charged off	11,165	9,048
Recoveries on Loans	2,288	2,281
Net loan charge-offs (recoveries)	8,877	6,767
Allowance for Credit Loss, Ending Balance	160,465	159,317	162,395
Liability for Unfunded Lending Commitments, Beginning Balance	25,246	33,120	33,120
Provision for credit losses on unfunded lending commitments	(2,160)	(4,492)
Liability for Unfunded Lending Commitments, Ending Balance	23,086	28,628	25,246
ALLOWANCE FOR CREDIT LOSSES ON LOANS AND LIABILITY FOR UNFUNDED LENDING COMMITMENTS	183,551	187,945
Commercial Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for Credit Loss, Beginning Balance	108,201	103,293	103,293
Provision for credit losses on loans	(2,855)	5,548
Loans charged off	316	292	3,885
Recoveries on Loans	434	66
Net loan charge-offs (recoveries)	(118)	226
Allowance for Credit Loss, Ending Balance	105,464	108,615	108,201
Liability for Unfunded Lending Commitments, Beginning Balance	23,909	31,743	31,743
Provision for credit losses on unfunded lending commitments	(2,273)	(4,638)
Liability for Unfunded Lending Commitments, Ending Balance	21,636	27,105	23,909
ALLOWANCE FOR CREDIT LOSSES ON LOANS AND LIABILITY FOR UNFUNDED LENDING COMMITMENTS	127,100	135,720
Personal Banking Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for Credit Loss, Beginning Balance	54,194	46,843	46,843
Provision for credit losses on loans	9,802	10,400
Loans charged off	10,849	8,756	36,283
Recoveries on Loans	1,854	2,215
Net loan charge-offs (recoveries)	8,995	6,541
Allowance for Credit Loss, Ending Balance	55,001	50,702	54,194
Liability for Unfunded Lending Commitments, Beginning Balance	1,337	1,377	1,377
Provision for credit losses on unfunded lending commitments	113	146
Liability for Unfunded Lending Commitments, Ending Balance	1,450	1,523	$ 1,337
ALLOWANCE FOR CREDIT LOSSES ON LOANS AND LIABILITY FOR UNFUNDED LENDING COMMITMENTS	$ 56,451	$ 52,225