Allowance for Loan and Lease Loss and Credit Quality (Non-Accrual Loans And Loans Past Due) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 75,658	$ 87,244
Non-Accrual	54,059	51,355
Current & Other	19,724,316	18,880,593
Total, non-covered loans and leases	19,854,033	19,019,192
GNMA Loans past due by 90 days, but not yet repurchased	8,000
Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current & Other	145,000	189,100
Greater than 30 to 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	14,666	20,686
60 to 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	19,159	23,167
90 Days and Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	41,833	43,391
Commercial real estate | Non-owner occupied term, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	2,304
Non-Accrual	11,379	4,503
Current & Other	3,515,978	3,476,390
Total, non-covered loans and leases	3,527,357	3,483,197
Commercial real estate | Owner occupied term, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	3,180	7,078
Non-Accrual	9,011	13,835
Current & Other	2,462,654	2,455,741
Total, non-covered loans and leases	2,474,845	2,476,654
Commercial real estate | Multifamily, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Non-Accrual	4,294	355
Current & Other	3,221,244	3,060,261
Total, non-covered loans and leases	3,225,538	3,060,616
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	646,684	540,696
Total, non-covered loans and leases	646,684	540,696
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	198,518	165,941
Total, non-covered loans and leases	198,518	165,941
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	0	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	354	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	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	0	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	2,776	2,010
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	50	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	106	1,661
Non-Accrual	10,860	14,686
Current & Other	2,138,410	1,928,578
Total, non-covered loans and leases	2,149,376	1,944,925
Commercial | Lines of credit & other, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	3,483	1,664
Non-Accrual	3,067	6,402
Current & Other	1,126,958	1,158,209
Total, non-covered loans and leases	1,133,508	1,166,275
Commercial | Leases & equipment finance, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	18,090	21,484
Non-Accrual	15,448	11,574
Current & Other	1,248,590	1,134,445
Total, non-covered loans and leases	1,282,128	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	21	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	2,916	1,263
Commercial | Greater than 30 to 59 Days Past Due | Leases & equipment finance, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	7,037	8,494
Commercial | 60 to 89 Days Past Due | Term, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	85	1,064
Commercial | 60 to 89 Days Past Due | Lines of credit & other, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	510	0
Commercial | 60 to 89 Days Past Due | Leases & equipment finance, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	7,967	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	57	401
Commercial | 90 Days and Accruing | Leases & equipment finance, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	3,086	2,857
Residential | Mortgage, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	42,043	43,689
Non-Accrual	0	0
Current & Other	3,426,526	3,139,199
Total, non-covered loans and leases	3,468,569	3,182,888
Residential | Home equity loans & lines, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	4,126	4,844
Non-Accrual	0	0
Current & Other	1,139,225	1,093,033
Total, non-covered loans and leases	1,143,351	1,097,877
Residential | Greater than 30 to 59 Days Past Due | Mortgage, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	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	1,436	2,011
Residential | 60 to 89 Days Past Due | Mortgage, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	5,840	6,709
Residential | 60 to 89 Days Past Due | Home equity loans & lines, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	999	283
Residential | 90 Days and Accruing | Mortgage, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	36,203	36,980
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	8,000	12,400
Residential | 90 Days and Accruing | Home equity loans & lines, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,691	2,550
Consumer & other, net
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	4,630	4,520
Non-Accrual	0	0
Current & Other	599,529	728,100
Total, non-covered loans and leases	604,159	732,620
Consumer & other, net | Greater than 30 to 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,902	3,117
Consumer & other, net | 60 to 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	982	871
Consumer & other, net | 90 Days and Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 746	$ 532