Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Securities available-for-sale, amortized cost	$ 898,434	$ 987,560
Less: Unearned income on loans	(11,523)	(16,217)
Other real estate owned covered by FDIC loss share	27,386	51,019
Common stock, par value
Common stock, shares authorized	63,033	63,033
Common stock, shares outstanding	39,689	39,506
Covered Loans [Member]
Allowance for losses on covered loans	(29,157)	(4,944)
Other real estate owned covered by FDIC loss share	$ 16,511	$ 28,126