Fair Value Of Financial Instruments (Estimated Fair Values And Carrying Amounts Of Financial Instruments) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2011	Dec. 31, 2010
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	$ 592,781	$ 573,296	$ 290,518	$ 337,778
FDIC loss share receivable	537,448	591,844
Derivative instruments	37,660	32,071
Deposits	9,461,411	9,289,013
Short-term borrowings	266,489	395,543
Long-term debt	429,841	452,733
Derivative instruments	35,262	35,010
Carrying Amount [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	592,781	573,296
Investment securities	2,001,107	1,997,969
Loans and loans held for sale	7,606,431	7,541,050
FDIC loss share receivable	537,448	591,844
Derivative instruments	37,660	32,071
Accrued interest receivable	31,409	36,006
Deposits	9,461,411	9,289,013
Short-term borrowings	266,489	395,543
Long-term debt	429,841	452,733
Derivative instruments	35,262	35,010
Accrued interest payable	6,194	6,978
Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	592,781	573,296
Investment securities	2,007,206	2,004,315
Loans and loans held for sale	7,947,402	7,916,049
FDIC loss share receivable	287,476	331,946
Derivative instruments	37,660	32,071
Accrued interest receivable	31,409	36,006
Deposits	9,391,784	9,262,698
Short-term borrowings	266,489	395,543
Long-term debt	395,906	418,069
Derivative instruments	35,262	35,010
Accrued interest payable	$ 6,194	$ 6,978