Allowance for Loan and Lease Loss and Credit Quality (Internal Risk Rating By Loan Class) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	$ 20,405,997	$ 20,422,666
GNMA Loans, right to repurchase	158
Pass/Watch
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	$ 20,036,064	$ 20,076,448
Percentage of impaired loans	5.50%	3.20%
Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	$ 214,901	$ 155,864
Percentage of impaired loans	10.20%	8.80%
Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	$ 102,049	$ 127,651
Percentage of impaired loans	84.30%	88.00%
Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	$ 13,582	$ 14,667
Loss
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	2,325	5,779
Impaired
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	37,076	42,257
Commercial real estate | Non-owner occupied term, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	3,476,972	3,573,065
Commercial real estate | Owner occupied term, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	2,449,648	2,480,371
Commercial real estate | Multifamily, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	3,302,936	3,304,763
Commercial real estate | Construction & development, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	686,107	736,254
Commercial real estate | Residential development, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	205,963	196,890
Commercial real estate | Pass/Watch | Non-owner occupied term, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	3,399,606	3,497,801
Commercial real estate | Pass/Watch | Owner occupied term, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	2,380,614	2,422,351
Commercial real estate | Pass/Watch | Multifamily, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	3,285,727	3,284,445
Commercial real estate | Pass/Watch | Construction & development, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	682,568	734,318
Commercial real estate | Pass/Watch | Residential development, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	205,963	196,890
Commercial real estate | Special Mention | Non-owner occupied term, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	46,954	38,346
Commercial real estate | Special Mention | Owner occupied term, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	45,634	28,447
Commercial real estate | Special Mention | Multifamily, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	11,132	11,481
Commercial real estate | Special Mention | Construction & development, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	1,608	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	18,444	23,234
Commercial real estate | Substandard | Owner occupied term, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	17,628	22,136
Commercial real estate | Substandard | Multifamily, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	3,451	4,539
Commercial real estate | Substandard | Construction & development, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	1,931	1,936
Commercial real estate | Substandard | Residential development, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	0	0
Commercial real estate | Doubtful | Non-owner occupied term, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	0	0
Commercial real estate | Doubtful | Owner occupied term, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	0	54
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	122
Commercial real estate | Loss | Owner occupied term, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	0	327
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	11,968	13,562
Commercial real estate | Impaired | Owner occupied term, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	5,772	7,056
Commercial real estate | Impaired | Multifamily, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	2,626	4,298
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	2,185,322	2,232,923
Commercial | Lines of credit & other, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	1,229,092	1,169,525
Commercial | Leases & equipment finance, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	1,378,686	1,330,155
Commercial | Pass/Watch | Term, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	2,122,335	2,196,753
Commercial | Pass/Watch | Lines of credit & other, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	1,178,625	1,103,677
Commercial | Pass/Watch | Leases & equipment finance, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	1,338,955	1,296,235
Commercial | Special Mention | Term, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	41,568	15,519
Commercial | Special Mention | Lines of credit & other, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	36,411	42,831
Commercial | Special Mention | Leases & equipment finance, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	14,105	8,571
Commercial | Substandard | Term, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	8,838	5,670
Commercial | Substandard | Lines of credit & other, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	12,350	20,639
Commercial | Substandard | Leases & equipment finance, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	7,560	8,754
Commercial | Doubtful | Term, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	319	53
Commercial | Doubtful | Lines of credit & other, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	222	313
Commercial | Doubtful | Leases & equipment finance, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	13,041	14,247
Commercial | Loss | Term, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	4	69
Commercial | Loss | Lines of credit & other, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	0	0
Commercial | Loss | Leases & equipment finance, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	2,057	1,931
Commercial | Impaired | Term, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	12,258	14,859
Commercial | Impaired | Lines of credit & other, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	1,484	2,065
Commercial | Impaired | Leases & equipment finance, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	2,968	417
Residential | Mortgage, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	3,768,955	3,635,073
Residential | Mortgage, net | Financing Receivables, Equal to Greater than 90 Days Past Due | GNMA Loans
Financing Receivable, Recorded Investment [Line Items]
GNMA Loans, right to repurchase	158	8,900
Residential | Home equity loans & lines, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	1,170,252	1,176,477
Residential | Pass/Watch | Mortgage, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	3,728,782	3,588,976
Residential | Pass/Watch | Home equity loans & lines, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	1,164,876	1,172,040
Residential | Special Mention | Mortgage, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	10,494	5,169
Residential | Special Mention | Home equity loans & lines, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	3,562	1,878
Residential | Substandard | Mortgage, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	29,615	38,766
Residential | Substandard | Home equity loans & lines, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	1,648	1,418
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	64	2,162
Residential | Loss | Home equity loans & lines, net
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	166	1,141
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	552,064	587,170
Consumer & other, net | Pass/Watch
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	548,013	582,962
Consumer & other, net | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	3,433	3,622
Consumer & other, net | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	584	559
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	34	27
Consumer & other, net | Impaired
Financing Receivable, Recorded Investment [Line Items]
Loans by credit quality	$ 0	$ 0