Loans And Allowance For Loan Losses (Credit Quality Of Commercial Loan Portfolio) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	$ 5,529,953	$ 5,374,963
Pass [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	5,174,442	4,968,667
Special Mention [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	119,848	94,865
Substandard [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	181,788	243,561
Non-Accrual [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	53,875	67,870
Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	2,993,067	2,808,265
Business [Member] | Pass [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	2,857,378	2,669,868
Business [Member] | Special Mention [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	65,052	37,460
Business [Member] | Substandard [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	56,514	75,213
Business [Member] | Non-Accrual [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	14,123	25,724
Real Estate - Construction And Land [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	346,048	386,598
Real Estate - Construction And Land [Member] | Pass [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	278,895	304,408
Real Estate - Construction And Land [Member] | Special Mention [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	5,739	4,722
Real Estate - Construction And Land [Member] | Substandard [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	43,216	54,696
Real Estate - Construction And Land [Member] | Non-Accrual [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	18,198	22,772
Real Estate - Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	2,190,838	2,180,100
Real Estate - Business [Member] | Pass [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	2,038,169	1,994,391
Real Estate - Business [Member] | Special Mention [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	49,057	52,683
Real Estate - Business [Member] | Substandard [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	82,058	113,652
Real Estate - Business [Member] | Non-Accrual [Member]
Loans And Allowance For Loan Losses [Line Items]
Carrying Amount	$ 21,554	$ 19,374