Loans And Allowance For Loan Losses (Credit Quality Of Commercial Loan Portfolio) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	$ 6,680,228	$ 6,435,066
Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	3,941,394	3,715,319
Business [Member] | Pass [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	3,840,105	3,618,120
Business [Member] | Special Mention [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	59,603	61,916
Business [Member] | Substandard [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	30,675	23,691
Business [Member] | Non-Accrual [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	11,011	11,592
Real Estate - Construction And Land [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	423,667	406,197
Real Estate - Construction And Land [Member] | Pass [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	391,080	372,515
Real Estate - Construction And Land [Member] | Special Mention [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	1,917	1,697
Real Estate - Construction And Land [Member] | Substandard [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	21,223	21,812
Real Estate - Construction And Land [Member] | Non-Accrual [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	9,447	10,173
Real Estate - Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	2,315,167	2,313,550
Real Estate - Business [Member] | Pass [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	2,193,862	2,190,344
Real Estate - Business [Member] | Special Mention [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	48,782	53,079
Real Estate - Business [Member] | Substandard [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	53,469	50,349
Real Estate - Business [Member] | Non-Accrual [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	19,054	19,778
Non-Accrual [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	39,512	41,543
Substandard [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	105,367	95,852
Special Mention [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	110,302	116,692
Pass [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	$ 6,425,047	$ 6,180,979