Income Taxes (Details 1) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Deferred tax assets:
Allowance for loan losses	$ 85,289	$ 30,356
Employee compensation and benefits	40,013	27,086
Loan purchase accounting adjustments	241,412	126,536
Demand deposits	2,308	1,218
Capital loss	0	153
Tax credit carryforward	25,465	663
Federal net operating loss	24,524	104
State net operating loss	2,958	1,274
Other	23,128	1,637
Gross deferred tax assets	445,097	189,027
Federal valuation allowance	0	(84)
State valuation allowance	(2,415)	(1,274)
Subtotal valuation allowance	(2,415)	(1,358)
Net deferred tax assets	442,682	187,669
Deferred tax liabilities:
Fixed assets & intangibles	(135,987)	(31,159)
FHLB Stock Dividend	(1,119)	(3,520)
Securities	(55,642)	(15,932)
Deferred gain on acquisition	(13,232)	(17,907)
FDIC Indemnification Asset	(83,348)	(104,785)
Other	(7,594)	(7,825)
Gross deferred tax liabilities	(296,922)	(181,128)
Net deferred tax asset (liability)	$ 145,760	$ 6,541