Loans And Allowance For Loan Losses (Credit Quality Of Commercial Loan Portfolio) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	$ 5,773,606	$ 5,705,772
Pass [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	5,478,806	5,419,131
Special Mention [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	124,804	108,589
Substandard [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	130,654	134,014
Non-Accrual [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	39,342	44,038
Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	3,206,594	3,134,801
Business [Member] | Pass [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	3,080,972	3,018,062
Business [Member] | Special Mention [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	69,708	58,793
Business [Member] | Substandard [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	43,835	44,890
Business [Member] | Non-Accrual [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	12,079	13,056
Real Estate - Construction And Land [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	353,659	355,996
Real Estate - Construction And Land [Member] | Pass [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	296,540	297,156
Real Estate - Construction And Land [Member] | Special Mention [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	8,660	11,400
Real Estate - Construction And Land [Member] | Substandard [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	35,485	33,762
Real Estate - Construction And Land [Member] | Non-Accrual [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	12,974	13,678
Real Estate - Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	2,213,353	2,214,975
Real Estate - Business [Member] | Pass [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	2,101,294	2,103,913
Real Estate - Business [Member] | Special Mention [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	46,436	38,396
Real Estate - Business [Member] | Substandard [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	51,334	55,362
Real Estate - Business [Member] | Non-Accrual [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	$ 14,289	$ 17,304