Loans And Allowance For Loan Losses (Credit Quality Of Commercial Loan Portfolio) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Loans And Allowance For Loan Losses [Line Items]
Loans	$ 13,091,888	$ 12,436,692
Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	4,840,248	4,397,893
Real Estate - Construction And Land [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	819,896	624,070
Real Estate - Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	2,399,271	2,355,544
Commercial Portfolio Segment [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	8,059,415	7,377,507
Commercial Portfolio Segment [Member] | Pass [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	7,829,267	7,179,210
Commercial Portfolio Segment [Member] | Special Mention [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	100,117	65,344
Commercial Portfolio Segment [Member] | Substandard [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	109,909	111,126
Commercial Portfolio Segment [Member] | Non-Accrual [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	20,122	21,827
Commercial Portfolio Segment [Member] | Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	4,840,248	4,397,893
Commercial Portfolio Segment [Member] | Business [Member] | Pass [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	4,702,346	4,278,857
Commercial Portfolio Segment [Member] | Business [Member] | Special Mention [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	66,786	49,302
Commercial Portfolio Segment [Member] | Business [Member] | Substandard [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	58,400	58,860
Commercial Portfolio Segment [Member] | Business [Member] | Non-Accrual [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	12,716	10,874
Commercial Portfolio Segment [Member] | Real Estate - Construction And Land [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	819,896	624,070
Commercial Portfolio Segment [Member] | Real Estate - Construction And Land [Member] | Pass [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	808,815	618,788
Commercial Portfolio Segment [Member] | Real Estate - Construction And Land [Member] | Special Mention [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	8,561	1,033
Commercial Portfolio Segment [Member] | Real Estate - Construction And Land [Member] | Substandard [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	350	1,159
Commercial Portfolio Segment [Member] | Real Estate - Construction And Land [Member] | Non-Accrual [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	2,170	3,090
Commercial Portfolio Segment [Member] | Real Estate - Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	2,399,271	2,355,544
Commercial Portfolio Segment [Member] | Real Estate - Business [Member] | Pass [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	2,318,106	2,281,565
Commercial Portfolio Segment [Member] | Real Estate - Business [Member] | Special Mention [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	24,770	15,009
Commercial Portfolio Segment [Member] | Real Estate - Business [Member] | Substandard [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	51,159	51,107
Commercial Portfolio Segment [Member] | Real Estate - Business [Member] | Non-Accrual [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	$ 5,236	$ 7,863