Allowance for Loan and Lease Loss and Credit Quality (Non-Accrual Loans And Leases and Loans and Leases Past Due) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	$ 87,292	$ 69,651
Nonaccrual	51,465	27,765
Current	18,941,427	17,411,247
Total, non-covered loans and leases	19,080,184	17,508,663
Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	189,100	280,400
Greater Than 30 to 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	20,678	12,587
60 to 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	23,192	17,838
Greater than 90 Days and Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	43,422	39,226
Commercial Real Estate | Non-owner Occupied Term, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	2,304	2,792
Nonaccrual	4,578	2,100
Current	3,484,255	3,325,550
Total, non-covered loans and leases	3,491,137	3,330,442
Commercial Real Estate | Owner Occupied Term, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	7,083	5,514
Nonaccrual	13,870	4,391
Current	2,467,298	2,589,150
Total, non-covered loans and leases	2,488,251	2,599,055
Commercial Real Estate | Multifamily, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	0
Nonaccrual	355	476
Current	3,087,437	2,858,480
Total, non-covered loans and leases	3,087,792	2,858,956
Commercial Real Estate | Construction & Development, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	0
Nonaccrual	0	0
Current	540,707	463,625
Total, non-covered loans and leases	540,707	463,625
Commercial Real Estate | Residential Development, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	0
Nonaccrual	0	0
Current	165,865	142,984
Total, non-covered loans and leases	165,865	142,984
Commercial Real Estate | Greater Than 30 to 59 Days Past Due | Non-owner Occupied Term, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	207	718
Commercial Real Estate | Greater Than 30 to 59 Days Past Due | Owner Occupied Term, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	4,997	974
Commercial Real Estate | Greater Than 30 to 59 Days Past Due | Multifamily, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	0
Commercial Real Estate | Greater Than 30 to 59 Days Past Due | Construction & Development, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	0
Commercial Real Estate | Greater Than 30 to 59 Days Past Due | Residential Development, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	0
Commercial Real Estate | 60 to 89 Days Past Due | Non-owner Occupied Term, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	2,097	1,027
Commercial Real Estate | 60 to 89 Days Past Due | Owner Occupied Term, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	2,015	4,539
Commercial Real Estate | 60 to 89 Days Past Due | Multifamily, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	0
Commercial Real Estate | 60 to 89 Days Past Due | Construction & Development, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	0
Commercial Real Estate | 60 to 89 Days Past Due | Residential Development, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	0
Commercial Real Estate | Greater than 90 Days and Accruing | Non-owner Occupied Term, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	1,047
Commercial Real Estate | Greater than 90 Days and Accruing | Owner Occupied Term, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	71	1
Commercial Real Estate | Greater than 90 Days and Accruing | Multifamily, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	0
Commercial Real Estate | Greater than 90 Days and Accruing | Construction & Development, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	0
Commercial Real Estate | Greater than 90 Days and Accruing | Residential Development, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	0
Commercial | Term, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	1,673	552
Nonaccrual	14,686	6,880
Current	1,928,628	1,501,348
Total, non-covered loans and leases	1,944,987	1,508,780
Commercial | LOC & Other, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	1,664	1,700
Nonaccrual	6,402	4,998
Current	1,158,107	1,109,561
Total, non-covered loans and leases	1,166,173	1,116,259
Commercial | Leases and Equipment Finance, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	21,484	14,016
Nonaccrual	11,574	8,920
Current	1,134,445	927,652
Total, non-covered loans and leases	1,167,503	950,588
Commercial | Greater Than 30 to 59 Days Past Due | Term, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	597	319
Commercial | Greater Than 30 to 59 Days Past Due | LOC & Other, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	1,263	1,673
Commercial | Greater Than 30 to 59 Days Past Due | Leases and Equipment Finance, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	8,494	5,343
Commercial | 60 to 89 Days Past Due | Term, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	1,076	233
Commercial | 60 to 89 Days Past Due | LOC & Other, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	27
Commercial | 60 to 89 Days Past Due | Leases and Equipment Finance, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	10,133	6,865
Commercial | Greater than 90 Days and Accruing | Term, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	0
Commercial | Greater than 90 Days and Accruing | LOC & Other, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	401	0
Commercial | Greater than 90 Days and Accruing | Leases and Equipment Finance, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	2,857	1,808
Residential | Mortgage, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	43,693	36,827
Nonaccrual	0	0
Current	3,148,492	2,851,144
Total, non-covered loans and leases	3,192,185	2,887,971
Residential | Home Equity Loans & Lines, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	4,876	3,217
Nonaccrual	0	0
Current	1,098,421	1,008,627
Total, non-covered loans and leases	1,103,297	1,011,844
Residential | Greater Than 30 to 59 Days Past Due | Mortgage, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	10
Residential | Greater Than 30 to 59 Days Past Due | Home Equity Loans & Lines, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	2,004	289
Residential | 60 to 89 Days Past Due | Mortgage, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	6,716	3,114
Residential | 60 to 89 Days Past Due | Home Equity Loans & Lines, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	285	848
Residential | Greater than 90 Days and Accruing | Mortgage, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	36,977	33,703
Residential | Greater than 90 Days and Accruing | Mortgage, net | GNMA
Financing Receivable, Recorded Investment, Past Due [Line Items]
GNMA Loans past due by 90 days, but not yet repurchased	12,400	10,900
Residential | Greater than 90 Days and Accruing | Home Equity Loans & Lines, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	2,587	2,080
Consumer & Other, Net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	4,515	5,033
Nonaccrual	0	0
Current	727,772	633,126
Total, non-covered loans and leases	732,287	638,159
Consumer & Other, Net | Greater Than 30 to 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	3,116	3,261
Consumer & Other, Net | 60 to 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	870	1,185
Consumer & Other, Net | Greater than 90 Days and Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	$ 529	$ 587