Loans and Allowance for Loan Losses (Details Textual) (USD $)	12 Months Ended																12 Months Ended			12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009	Dec. 31, 2011 Covered Loans [Member]		Dec. 31, 2010 Covered Loans [Member]		Dec. 31, 2011 Acquired Loans (Noncovered) [Member]	Dec. 31, 2010 Acquired Loans (Noncovered) [Member]	Dec. 31, 2011 Loss Share Receivable [Member]	Dec. 31, 2010 Loss Share Receivable [Member]	Feb. 19, 2010 George Washington Transaction [Member]	May 14, 2010 Midwest Transaction [Member]	Feb. 19, 2010 First Bank Branches [Member]	Dec. 31, 2011 Consumer Loans [Member]	Dec. 31, 2011 Acquired Impaired Loans [Member]	Dec. 31, 2010 Acquired Impaired Loans [Member]	Dec. 31, 2011 Commercial Loan [Member]	Dec. 31, 2011 Impaired Loans with No Related Allowance [Member]	Dec. 31, 2010 Impaired Loans with No Related Allowance [Member]
Loans (Textual) [Abstract]
Total noncovered loans	$ 7,748,944,000	[1]	$ 7,202,088,000	[1]						$ 113,200,000	$ 265,500,000
Loss share receivable excluded from covered loans	205,700,000		288,600,000
Covered Loans and Leases Receivable Gross	1,497,140,000	[2]	1,976,754,000	[2]								205,700,000	288,600,000
Net of deferred loan origination fee and cost	6,000,000		3,600,000
Bank acquired loans														275,600,000	1,800,000,000	177,800,000
Outstanding balance, including contractual principal, interest, fees and penalties, of all purchased loans	1,600,000,000
Acquired Non Impaired Loans	162,600,000
Increase in allowance for covered loan losses			13,733,000			36,400,000
Provision for noncovered loan losses	62,900,000		83,783,000		98,433,000	20,353,000		4,432,000
Increased in loss share receivable	42,600,000
Acquired impaired loans including troubled debt restructurings	72,900,000		46,800,000
Allowance associated, Impaired Loans	7,080,000		6,181,000																		3,500,000	1,000,000
Investment In Non Covered Loans	1,800,000
Financing Receivable, Modifications, Recorded Investment	150,355,000					77,419,000											300,000
Financing receivable modifications nonaccrual loans																	23,900,000
Allowance for credit losses associated with noncovered loans										200,000							1,300,000
Trouble debt restructurings on acquired impaired loans																		77,400,000	37,200,000
Investment in Covered Loans Considered as TDR	1,900,000
Loans charged off			104,532,000		99,713,000	40,221,000		13,451,000												4,300,000
Recorded investment of consumer loans																	3,700,000
Total Loans						1,291,476,000	[3]	1,688,149,000	[4]	113,168,000	265,501,000
Loss share receivable	205,700,000		288,600,000
Investment in nonaccrual loans										2,949,000	93,000
Accruing interest on investment										3,000	810,000
Interest income	$ 405,239,000		$ 370,304,000		$ 250,331,000

[1] Includes acquired, non-covered loans of $113.2 million and $265.5 million as of December 31, 2011 and 2010, respectively.

[2] Includes loss share receivable of $205.7 million and $288.6 million as of December 31, 2011 and 2010, respectively.

[3] Excludes loss share receivable of $205.7 million as of December 31, 2011.

[4] Excludes loss share receivable of $288.6 million as of December 31, 2010.