Loans And Allowance For Loan Losses (Credit Quality Of Commercial Loan Portfolio) (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Loans And Allowance For Loan Losses [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount, Commercial	$ 7,227,292	$ 6,661,674
Pass [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount, Commercial	7,043,813	6,441,941
Special Mention [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount, Commercial	80,123	107,437
Substandard [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount, Commercial	82,557	77,713
Non-Accrual [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount, Commercial	20,799	34,583
Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount, Commercial	4,406,854	3,969,952
Business [Member] | Pass [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount, Commercial	4,304,836	3,871,569
Business [Member] | Special Mention [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount, Commercial	59,526	62,904
Business [Member] | Substandard [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount, Commercial	30,793	23,919
Business [Member] | Non-Accrual [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount, Commercial	11,699	11,560
Real Estate - Construction And Land [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount, Commercial	534,425	403,507
Real Estate - Construction And Land [Member] | Pass [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount, Commercial	527,590	385,831
Real Estate - Construction And Land [Member] | Special Mention [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount, Commercial	1,021	3,865
Real Estate - Construction And Land [Member] | Substandard [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount, Commercial	1,768	8,654
Real Estate - Construction And Land [Member] | Non-Accrual [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount, Commercial	4,046	5,157
Real Estate - Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount, Commercial	2,286,013	2,288,215
Real Estate - Business [Member] | Pass [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount, Commercial	2,211,387	2,184,541
Real Estate - Business [Member] | Special Mention [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount, Commercial	19,576	40,668
Real Estate - Business [Member] | Substandard [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount, Commercial	49,996	45,140
Real Estate - Business [Member] | Non-Accrual [Member]
Loans And Allowance For Loan Losses [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount, Commercial	$ 5,054	$ 17,866