Other Real Estate Owned and Property Acquired in Settlement of Loans (Details) (USD $)	3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012		Mar. 31, 2012	Dec. 31, 2011
Repossessed Assets [Abstract]
Decrease in total OREO and foreclosed assets	$ 16,600,000
Total OREO and foreclosed assets as a percentage of total nonperforming assets	40.00%	44.00%
Real estate acquired in settlement of loans	46,307,000	62,796,000		104,193,000	110,009,000
Personal property acquired in settlement of loans	230,000	335,000
Total property acquired in settlement of loans	$ 46,537,000	$ 63,131,000	[1]

[1] Derived from audited consolidated financial statements