Allowance for Losses and Concentration of Credit Risk - Narrative (Details) (USD $) In Thousands, unless otherwise specified			9 Months Ended
	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2012 Minimum	Sep. 30, 2012 Maximum
Allowance for Losses and Concentrations of Credit Risk [Abstract]
Allowance for Losses, evaluated individually for impairment	$ 8,011	$ 7,296
Financing Receivable, Allowance for Credit Losses [Line Items]
Period past due for acquired delinquent loans			90 days	120 days