Loans And Allowance For Loan Losses (Credit Quality Of Commercial Loan Portfolio) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Loans And Allowance For Loan Losses [Line Items]
Total	$ 5,500,565	$ 5,374,963
Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	2,920,237	2,808,265
Real Estate - Construction And Land [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	376,642	386,598
Real Estate - Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	2,203,686	2,180,100
Pass [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	5,115,307	4,968,667
Pass [Member] | Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	2,781,156	2,669,868
Pass [Member] | Real Estate - Construction And Land [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	300,425	304,408
Pass [Member] | Real Estate - Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	2,033,726	1,994,391
Special Mention [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	127,824	94,865
Special Mention [Member] | Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	65,202	37,460
Special Mention [Member] | Real Estate - Construction And Land [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	6,525	4,722
Special Mention [Member] | Real Estate - Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	56,097	52,683
Substandard [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	195,582	243,561
Substandard [Member] | Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	53,737	75,213
Substandard [Member] | Real Estate - Construction And Land [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	48,637	54,696
Substandard [Member] | Real Estate - Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	93,208	113,652
Non-Accrual [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	61,852	67,870
Non-Accrual [Member] | Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	20,142	25,724
Non-Accrual [Member] | Real Estate - Construction And Land [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	21,055	22,772
Non-Accrual [Member] | Real Estate - Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total	$ 20,655	$ 19,374