Loans and the Allowance for Credit Losses (Details) - Past Due Financing Receivables - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	$ 80,535	$ 84,625
Nonaccrual	59,403	61,700
Gross Loans	6,987,973	6,838,351
30-59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	8,752	7,364
60-89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual		2,030
90 Days or Greater Past Due and Still Accruing [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	12,380	13,531
Current [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	6,907,438	6,753,726
Commercial Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	38,322	39,553
Nonaccrual	30,341	30,062
Gross Loans	1,278,477	1,299,428
Commercial Portfolio Segment [Member] \| 30-59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	3,561	4,305
Commercial Portfolio Segment [Member] \| 60-89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual		729
Commercial Portfolio Segment [Member] \| 90 Days or Greater Past Due and Still Accruing [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	4,420	4,457
Commercial Portfolio Segment [Member] \| Current [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	1,240,155	1,259,875
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	35,262	33,959
Nonaccrual	26,316	25,393
Gross Loans	4,919,093	4,741,590
Commercial Real Estate Portfolio Segment [Member] \| 30-59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	3,098	1,622
Commercial Real Estate Portfolio Segment [Member] \| 60-89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual		1,009
Commercial Real Estate Portfolio Segment [Member] \| 90 Days or Greater Past Due and Still Accruing [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	5,848	5,935
Commercial Real Estate Portfolio Segment [Member] \| Current [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	4,883,831	4,707,631
Commercial Construction Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	123	3,150
Nonaccrual		3,150
Gross Loans	539,058	540,178
Commercial Construction Portfolio Segment [Member] \| 30-59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	123
Commercial Construction Portfolio Segment [Member] \| 60-89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual
Commercial Construction Portfolio Segment [Member] \| 90 Days or Greater Past Due and Still Accruing [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual
Commercial Construction Portfolio Segment [Member] \| Current [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	538,935	537,028
Residential Real Estate Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	6,203	7,963
Nonaccrual	2,746	3,095
Gross Loans	250,205	255,269
Residential Real Estate Portfolio Segment [Member] \| 30-59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	1,970	1,437
Residential Real Estate Portfolio Segment [Member] \| 60-89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual		292
Residential Real Estate Portfolio Segment [Member] \| 90 Days or Greater Past Due and Still Accruing [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	1,487	3,139
Residential Real Estate Portfolio Segment [Member] \| Current [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	244,002	247,306
Consumer Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	625
Nonaccrual
Gross Loans	1,140	1,886
Consumer Portfolio Segment [Member] \| 30-59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual
Consumer Portfolio Segment [Member] \| 60-89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual
Consumer Portfolio Segment [Member] \| 90 Days or Greater Past Due and Still Accruing [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	625
Consumer Portfolio Segment [Member] \| Current [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	$ 515	$ 1,886