Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Securities available-for-sale, amortized cost	$ 987,560	$ 743,928
Other real estate owned covered by FDIC loss share	51,019	45,434
Common stock, par value
Common stock, shares authorized	63,033	63,033
Common stock, outstanding	39,506	39,338
Noncovered Loans [Member]
Unearned income on loans	(16,217)	(3,490)
Allowance for losses	(53,041)	(60,993)
Other real estate owned covered by FDIC loss share	22,893	30,991
Covered Loans [Member]
Allowance for losses	(4,944)	(6,055)
Other real estate owned covered by FDIC loss share	$ 28,126	$ 14,443