Fair Value Part 3 (Details) (USD $)	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Apr. 15, 2011	Dec. 31, 2010
Fair Values, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	$ 2,399,042,000			$ 2,177,249,000
Securities held to maturity	87,923,000			140,847,000
Loans held for sale	123,244,000			153,044,000
Net LHFI, excluding covered loans	5,819,470,000			5,966,732,000
Covered loans	88,558,000			0
FDIC indemnification asset	33,327,000		33,333,000	0
Other assets - derivatives	781,000			(2,247,000)
Deposits	7,632,334,000			7,044,567,000
Long-term FHLB advances	(2,794,000)			0
Subordinated notes	49,823,000			49,806,000
Junior subordinated debt securities	61,856,000			61,856,000
Other liabilities - derivatives	(1,888,000)			1,581,000
Outstanding balances in impaired loans	75,100,000			97,600,000
Nonfinancial Assets and Liabilities [Abstract]
Foreclosed assets measured at fair value	32,900,000	34,000,000
Allowance for possible loan losses, Charge-offs	5,200,000	3,900,000
Foreclosed assets re-measured after initial recognition	42,700,000	24,300,000
Write-downs Of Allowance For Foreclosed Assets After Initial Recognition	6,400,000	7,900,000
Estimated fair value of financial instruments with immediate and shorter-term maturities maximum (in days)	90 days or less
Family residential properties, bedrooms (minimum)	1
Family residential properties (maximum)	4
Fair Value, Measurements, Recurring [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member]
Fair Values, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and short-term investments	226,429,000			173,317,000
Securities available for sale	2,399,042,000			2,177,249,000
Securities held to maturity	87,923,000			140,847,000
Loans held for sale	123,244,000			153,044,000
Net LHFI, excluding covered loans	5,819,470,000			5,966,732,000
Covered loans	88,558,000			0
FDIC indemnification asset	33,327,000			0
Other assets - derivatives	781,000			(2,247,000)
Deposits	7,632,334,000			7,044,567,000
Short-term liabilities	629,849,000			1,125,481,000
Long-term FHLB advances	2,794,000			0
Subordinated notes	49,823,000			49,806,000
Junior subordinated debt securities	61,856,000			61,856,000
Other liabilities - derivatives	1,888,000			(1,581,000)
Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Values, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and short-term investments	226,429,000			173,317,000
Securities available for sale	2,399,042,000			2,177,249,000
Securities held to maturity	92,149,000			145,143,000
Loans held for sale	123,244,000			153,044,000
Net LHFI, excluding covered loans	5,873,407,000			6,030,219,000
Covered loans	88,558,000			0
FDIC indemnification asset	33,327,000			0
Other assets - derivatives	781,000			(2,247,000)
Deposits	7,640,533,000			7,054,611,000
Short-term liabilities	629,849,000			1,125,481,000
Long-term FHLB advances	2,794,000			0
Subordinated notes	50,400,000			48,750,000
Junior subordinated debt securities	35,876,000			30,928,000
Other liabilities - derivatives	$ 1,888,000			$ (1,581,000)