Allowance for Credit Losses (Non-Accrual Loans and Leases and Loans and Leases Past Due) (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	$ 59,790	$ 108,408
Non-Accrual	20,673	31,076
Current & Other	22,063,276	21,639,883
Total Loans and Leases	22,143,739	21,779,367
Financing Receivable, Allowance For Non-Accrual Credit Losses	6,300	16,700
Loans Deferred Under CARES Act	167,300	355,500
Total Non-Accrual Loans [Member]
Financing Receivable, Past Due [Line Items]
Non-Accrual	20,700	31,100
Greater than 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	13,613	24,791
60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	17,033	47,256
Greater than 90 Days and Accruing
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	29,144	36,361
Commercial real estate | Non-owner occupied term, net
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	434	23,338
Non-Accrual	3,563	3,809
Current & Other	3,576,389	3,478,655
Total Loans and Leases	3,580,386	3,505,802
Commercial real estate | Owner occupied term, net
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	2,022	493
Non-Accrual	5,471	5,984
Current & Other	2,390,833	2,327,468
Total Loans and Leases	2,398,326	2,333,945
Commercial real estate | Multifamily, net
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	578	215
Non-Accrual	0	0
Current & Other	3,553,126	3,348,981
Total Loans and Leases	3,553,704	3,349,196
Commercial real estate | Construction & development, net
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0	3,991
Non-Accrual	0	0
Current & Other	857,866	824,487
Total Loans and Leases	857,866	828,478
Commercial real estate | Residential development, net
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0	0
Non-Accrual	0	0
Current & Other	193,904	192,761
Total Loans and Leases	193,904	192,761
Commercial real estate | Greater than 30 to 59 Days Past Due | Non-owner occupied term, net
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0	1,214
Commercial real estate | Greater than 30 to 59 Days Past Due | Owner occupied term, net
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	224	182
Commercial real estate | Greater than 30 to 59 Days Past Due | Multifamily, net
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	578	0
Commercial real estate | Greater than 30 to 59 Days Past Due | Construction & development, net
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0	3,991
Commercial real estate | Greater than 30 to 59 Days Past Due | Residential development, net
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0	0
Commercial real estate | 60 to 89 Days Past Due | Non-owner occupied term, net
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	434	21,309
Commercial real estate | 60 to 89 Days Past Due | Owner occupied term, net
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	1,797	103
Commercial real estate | 60 to 89 Days Past Due | Multifamily, net
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0	215
Commercial real estate | 60 to 89 Days Past Due | Construction & development, net
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0	0
Commercial real estate | 60 to 89 Days Past Due | Residential development, net
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0	0
Commercial real estate | Greater than 90 Days and Accruing | Non-owner occupied term, net
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0	815
Commercial real estate | Greater than 90 Days and Accruing | Owner occupied term, net
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	1	208
Commercial real estate | Greater than 90 Days and Accruing | Multifamily, net
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0	0
Commercial real estate | Greater than 90 Days and Accruing | Construction & development, net
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0	0
Commercial real estate | Greater than 90 Days and Accruing | Residential development, net
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0	0
Commercial | Term, net
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	414	566
Non-Accrual	3,875	2,205
Current & Other	3,743,980	4,021,696
Total Loans and Leases	3,748,269	4,024,467
Commercial | Lines of credit & other, net
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	3,275	4,165
Non-Accrual	124	336
Current & Other	905,119	858,259
Total Loans and Leases	908,518	862,760
Commercial | Leases & equipment finance, net
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	19,145	37,258
Non-Accrual	7,640	18,742
Current & Other	1,410,587	1,400,630
Total Loans and Leases	1,437,372	1,456,630
Commercial | Greater than 30 to 59 Days Past Due | Term, net
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	265	562
Commercial | Greater than 30 to 59 Days Past Due | Lines of credit & other, net
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	194	1,491
Commercial | Greater than 30 to 59 Days Past Due | Leases & equipment finance, net
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	8,933	14,242
Commercial | 60 to 89 Days Past Due | Term, net
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	141	0
Commercial | 60 to 89 Days Past Due | Lines of credit & other, net
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	3,080	2,667
Commercial | 60 to 89 Days Past Due | Leases & equipment finance, net
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	7,966	18,220
Commercial | Greater than 90 Days and Accruing | Term, net
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	8	4
Commercial | Greater than 90 Days and Accruing | Lines of credit & other, net
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	1	7
Commercial | Greater than 90 Days and Accruing | Leases & equipment finance, net
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	2,246	4,796
Residential | Mortgage, net
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	29,427	33,212
Non-Accrual	0	0
Current & Other	4,116,005	3,838,694
Total Loans and Leases	4,145,432	3,871,906
Residential | Home equity loans & lines, net
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	3,096	3,851
Non-Accrual	0	0
Current & Other	1,115,182	1,132,213
Total Loans and Leases	1,118,278	1,136,064
Residential | Greater than 30 to 59 Days Past Due | Mortgage, net
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	1,422	1,587
Residential | Greater than 30 to 59 Days Past Due | Home equity loans & lines, net
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	1,195	844
Residential | 60 to 89 Days Past Due | Mortgage, net
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	3,117	3,912
Residential | 60 to 89 Days Past Due | Home equity loans & lines, net
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	141	544
Residential | Greater than 90 Days and Accruing | Mortgage, net
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	24,888	27,713
Residential | Greater than 90 Days and Accruing | Home equity loans & lines, net
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	1,760	2,463
Consumer & Other
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	1,399	1,319
Non-Accrual	0	0
Current & Other	200,285	216,039
Total Loans and Leases	201,684	217,358
Consumer & Other | Greater than 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	802	678
Consumer & Other | 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	357	286
Consumer & Other | Greater than 90 Days and Accruing
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	$ 240	$ 355