Allowance for Loan and Lease Loss and Credit Quality (Non-Accrual Loans And Loans Past Due) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 70,404	$ 87,292
Non-Accrual	45,775	51,465
Current & Other	19,198,410	18,941,427
Total, non-covered loans and leases	19,314,589	19,080,184
GNMA Loans past due by 90 days, but not yet repurchased	6,300
Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current & Other	173,500	189,100
Greater than 30 to 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	27,913	20,678
60 to 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	10,737	23,192
90 Days and Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	31,754	43,422
Commercial real estate | Non-owner occupied term, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,875	2,304
Non-Accrual	2,364	4,578
Current & Other	3,520,982	3,484,255
Total, non-covered loans and leases	3,526,221	3,491,137
Commercial real estate | Owner occupied term, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	3,083	7,083
Non-Accrual	12,341	13,870
Current & Other	2,460,863	2,467,298
Total, non-covered loans and leases	2,476,287	2,488,251
Commercial real estate | Multifamily, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	161	0
Non-Accrual	344	355
Current & Other	3,130,770	3,087,437
Total, non-covered loans and leases	3,131,275	3,087,792
Commercial real estate | Construction & development, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Non-Accrual	0	0
Current & Other	522,680	540,707
Total, non-covered loans and leases	522,680	540,707
Commercial real estate | Residential development, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Non-Accrual	0	0
Current & Other	179,871	165,865
Total, non-covered loans and leases	179,871	165,865
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	2,398	207
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	3,083	4,997
Commercial real estate | Greater than 30 to 59 Days Past Due | Multifamily, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	161	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	477	2,097
Commercial real estate | 60 to 89 Days Past Due | Owner occupied term, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	2,015
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 | 90 Days and Accruing | Non-owner occupied term, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Commercial real estate | 90 Days and Accruing | Owner occupied term, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	71
Commercial real estate | 90 Days and Accruing | Multifamily, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Commercial real estate | 90 Days and Accruing | Construction & development, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Commercial real estate | 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	1,942	1,673
Non-Accrual	14,331	14,686
Current & Other	2,008,940	1,928,628
Total, non-covered loans and leases	2,025,213	1,944,987
Commercial | Lines of credit & other, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,005	1,664
Non-Accrual	3,088	6,402
Current & Other	1,142,935	1,158,107
Total, non-covered loans and leases	1,147,028	1,166,173
Commercial | Leases and equipment finance, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	18,392	21,484
Non-Accrual	13,307	11,574
Current & Other	1,197,010	1,134,445
Total, non-covered loans and leases	1,228,709	1,167,503
Commercial | Greater than 30 to 59 Days Past Due | Term, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,891	597
Commercial | Greater than 30 to 59 Days Past Due | Lines of credit & other, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	941	1,263
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	11,223	8,494
Commercial | 60 to 89 Days Past Due | Term, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	51	1,076
Commercial | 60 to 89 Days Past Due | Lines of credit & other, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	64	0
Commercial | 60 to 89 Days Past Due | Leases and equipment finance, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	7,169	10,133
Commercial | 90 Days and Accruing | Term, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Commercial | 90 Days and Accruing | Lines of credit & other, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	401
Commercial | 90 Days and Accruing | Leases and equipment finance, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	2,857
Residential | Mortgage, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	36,051	43,693
Non-Accrual	0	0
Current & Other	3,247,894	3,148,492
Total, non-covered loans and leases	3,283,945	3,192,185
Residential | Home equity loans & lines, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	4,092	4,876
Non-Accrual	0	0
Current & Other	1,103,730	1,098,421
Total, non-covered loans and leases	1,107,822	1,103,297
Residential | Greater than 30 to 59 Days Past Due | Mortgage, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	4,985	0
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	1,252	2,004
Residential | 60 to 89 Days Past Due | Mortgage, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,955	6,716
Residential | 60 to 89 Days Past Due | Home equity loans & lines, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	454	285
Residential | 90 Days and Accruing | Mortgage, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	29,111	36,977
Residential | 90 Days and Accruing | Mortgage, net | GNMA Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
GNMA Loans past due by 90 days, but not yet repurchased	6,300	12,400
Residential | 90 Days and Accruing | Home equity loans & lines, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,386	2,587
Consumer & other, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,803	4,515
Non-Accrual	0	0
Current & Other	682,735	727,772
Total, non-covered loans and leases	685,538	732,287
Consumer & other, net | Greater than 30 to 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,979	3,116
Consumer & other, net | 60 to 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	567	870
Consumer & other, net | 90 Days and Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 257	$ 529