Allowance for Loan and Lease Loss and Credit Quality (Internal Risk Rating By Loan Class) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	$ 19,314,589	$ 19,080,184
GNMA Loans, rigt to repurchase	6,300
Pass/Watch
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	$ 18,930,024	$ 18,701,370
Percentage of impaired loans	2.20%	1.70%
Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	$ 165,059	$ 131,617
Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	$ 150,658	$ 166,751
Percentage of impaired loans	97.80%	98.30%
Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	$ 11,275	$ 14,080
Loss
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	5,632	6,390
Impaired
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	51,941	59,976
Commercial real estate | Non-owner occupied term, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	3,526,221	3,491,137
Commercial real estate | Owner occupied term, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	2,476,287	2,488,251
Commercial real estate | Multifamily, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	3,131,275	3,087,792
Commercial real estate | Construction & development, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	522,680	540,707
Commercial real estate | Residential development, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	179,871	165,865
Commercial real estate | Pass/Watch | Non-owner occupied term, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	3,438,686	3,396,178
Commercial real estate | Pass/Watch | Owner occupied term, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	2,398,088	2,409,301
Commercial real estate | Pass/Watch | Multifamily, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	3,101,489	3,064,079
Commercial real estate | Pass/Watch | Construction & development, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	518,676	538,526
Commercial real estate | Pass/Watch | Residential development, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	179,871	165,426
Commercial real estate | Special Mention | Non-owner occupied term, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	41,494	45,189
Commercial real estate | Special Mention | Owner occupied term, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	40,054	30,393
Commercial real estate | Special Mention | Multifamily, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	13,298	14,200
Commercial real estate | Special Mention | Construction & development, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	1,833	0
Commercial real estate | Special Mention | Residential development, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	0	0
Commercial real estate | Substandard | Non-owner occupied term, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	32,609	33,143
Commercial real estate | Substandard | Owner occupied term, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	27,239	35,191
Commercial real estate | Substandard | Multifamily, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	12,625	5,639
Commercial real estate | Substandard | Construction & development, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	2,171	2,181
Commercial real estate | Substandard | Residential development, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	0	439
Commercial real estate | Doubtful | Non-owner occupied term, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	107	630
Commercial real estate | Doubtful | Owner occupied term, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	0	448
Commercial real estate | Doubtful | Multifamily, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	0	0
Commercial real estate | Doubtful | Construction & development, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	0	0
Commercial real estate | Doubtful | Residential development, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	0	0
Commercial real estate | Loss | Non-owner occupied term, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	0	84
Commercial real estate | Loss | Owner occupied term, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	196	706
Commercial real estate | Loss | Multifamily, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	0	0
Commercial real estate | Loss | Construction & development, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	0	0
Commercial real estate | Loss | Residential development, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	0	0
Commercial real estate | Impaired | Non-owner occupied term, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	13,325	15,913
Commercial real estate | Impaired | Owner occupied term, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	10,710	12,212
Commercial real estate | Impaired | Multifamily, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	3,863	3,874
Commercial real estate | Impaired | Construction & development, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	0	0
Commercial real estate | Impaired | Residential development, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	0	0
Commercial | Term, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	2,025,213	1,944,987
Commercial | Lines of credit & other, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	1,147,028	1,166,173
Commercial | Leases and equipment finance, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	1,228,709	1,167,503
Commercial | Pass/Watch | Term, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	1,963,577	1,900,230
Commercial | Pass/Watch | Lines of credit & other, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	1,107,212	1,122,258
Commercial | Pass/Watch | Leases and equipment finance, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	1,197,468	1,134,446
Commercial | Special Mention | Term, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	31,646	12,735
Commercial | Special Mention | Lines of credit & other, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	13,420	6,539
Commercial | Special Mention | Leases and equipment finance, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	11,223	8,494
Commercial | Substandard | Term, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	9,047	10,266
Commercial | Substandard | Lines of credit & other, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	23,324	30,941
Commercial | Substandard | Leases and equipment finance, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	7,169	10,133
Commercial | Doubtful | Term, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	43	82
Commercial | Doubtful | Lines of credit & other, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	0	52
Commercial | Doubtful | Leases and equipment finance, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	11,125	12,868
Commercial | Loss | Term, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	70	80
Commercial | Loss | Lines of credit & other, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	3	0
Commercial | Loss | Leases and equipment finance, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	1,580	1,562
Commercial | Impaired | Term, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	20,830	21,594
Commercial | Impaired | Lines of credit & other, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	3,069	6,383
Commercial | Impaired | Leases and equipment finance, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	144	0
Residential | Mortgage, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	3,283,945	3,192,185
Residential | Mortgage, net | Financing Receivables, Equal to Greater than 90 Days Past Due | GNMA Loans
Financing Receivable, Recorded Investment [Line Items]
GNMA Loans, rigt to repurchase	6,300	12,400
Residential | Home equity loans & lines, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	1,107,822	1,103,297
Residential | Pass/Watch | Mortgage, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	3,239,104	3,145,363
Residential | Pass/Watch | Home equity loans & lines, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	1,103,210	1,097,886
Residential | Special Mention | Mortgage, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	7,545	7,512
Residential | Special Mention | Home equity loans & lines, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	2,003	2,558
Residential | Substandard | Mortgage, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	33,920	35,928
Residential | Substandard | Home equity loans & lines, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	2,270	2,322
Residential | Doubtful | Mortgage, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	0	0
Residential | Doubtful | Home equity loans & lines, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	0	0
Residential | Loss | Mortgage, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	3,376	3,382
Residential | Loss | Home equity loans & lines, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	339	531
Residential | Impaired | Mortgage, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	0	0
Residential | Impaired | Home equity loans & lines, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	0	0
Consumer & other, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	685,538	732,287
Consumer & other, net | Pass/Watch
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	682,643	727,677
Consumer & other, net | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	2,543	3,997
Consumer & other, net | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	284	568
Consumer & other, net | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	0	0
Consumer & other, net | Loss
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	68	45
Consumer & other, net | Impaired
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	$ 0	$ 0