CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
ASSETS
Investment securities available-for-sale, amortized cost	$ 3,132,968	$ 2,900,410
Allowance for loan losses, loans receivable	209,876	230,408
Allowance for loan losses, covered loans	$ 6,647	$ 4,225
STOCKHOLDERS' EQUITY
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized	5,000,000	5,000,000
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	156,798,011	155,743,241
Common stock, shares outstanding	149,327,907	148,542,940
Treasury stock, shares	7,470,104	7,200,301
Preferred stock, Series A, non-cumulative convertible
STOCKHOLDERS' EQUITY
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	200,000	200,000
Preferred stock, shares outstanding	85,710	85,741