CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
ASSETS
Investment securities available-for-sale, amortized cost	$ 2,737,687	$ 3,132,968
Allowance for loan losses, loans receivable	214,253	209,876
Allowance for loan losses, covered loans	$ 8,268	$ 6,647
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	157,003,114	156,798,011
Common stock, shares outstanding	144,870,621	149,327,907
Treasury stock, shares	12,132,493	7,470,104
Preferred stock, Series A, non-cumulative convertible
STOCKHOLDERS' EQUITY
Preferred stock, shares issued	200,000	200,000
Preferred stock, shares outstanding	85,710	85,710