Loans And Allowance For Loan Losses (Credit Quality Of Commercial Loan Portfolio) (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Loans And Allowance For Loan Losses [Line Items]
Loans	$ 13,230,241	$ 12,436,692
Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	4,770,883	4,397,893
Real Estate - Construction And Land [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	800,545	624,070
Real Estate - Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	2,520,528	2,355,544
Commercial Portfolio Segment [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	8,091,956	7,377,507
Commercial Portfolio Segment [Member] | Pass [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	7,844,670	7,179,210
Commercial Portfolio Segment [Member] | Special Mention [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	123,246	65,344
Commercial Portfolio Segment [Member] | Substandard [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	112,052	111,126
Commercial Portfolio Segment [Member] | Non-Accrual [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	11,988	21,827
Commercial Portfolio Segment [Member] | Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	4,770,883	4,397,893
Commercial Portfolio Segment [Member] | Business [Member] | Pass [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	4,625,175	4,278,857
Commercial Portfolio Segment [Member] | Business [Member] | Special Mention [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	76,105	49,302
Commercial Portfolio Segment [Member] | Business [Member] | Substandard [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	60,845	58,860
Commercial Portfolio Segment [Member] | Business [Member] | Non-Accrual [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	8,758	10,874
Commercial Portfolio Segment [Member] | Real Estate - Construction And Land [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	800,545	624,070
Commercial Portfolio Segment [Member] | Real Estate - Construction And Land [Member] | Pass [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	798,168	618,788
Commercial Portfolio Segment [Member] | Real Estate - Construction And Land [Member] | Special Mention [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	860	1,033
Commercial Portfolio Segment [Member] | Real Estate - Construction And Land [Member] | Substandard [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	207	1,159
Commercial Portfolio Segment [Member] | Real Estate - Construction And Land [Member] | Non-Accrual [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	1,310	3,090
Commercial Portfolio Segment [Member] | Real Estate - Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	2,520,528	2,355,544
Commercial Portfolio Segment [Member] | Real Estate - Business [Member] | Pass [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	2,421,327	2,281,565
Commercial Portfolio Segment [Member] | Real Estate - Business [Member] | Special Mention [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	46,281	15,009
Commercial Portfolio Segment [Member] | Real Estate - Business [Member] | Substandard [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	51,000	51,107
Commercial Portfolio Segment [Member] | Real Estate - Business [Member] | Non-Accrual [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans	$ 1,920	$ 7,863