Covered Assets and FDIC Loss-sharing Asset (Narrative) (Details) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Covered Assets And FDIC Loss Sharing Asset [Line Items]
Amount of Estimated Clawback Liability	$ 3,800,000
Payment Of Clawback If Losses Less Than Stated Levels, Period After Acquisition	10 years 45 days
Provision for loan and lease losses	(20,000)	20,185,000
Federal deposit insurance corporation loss-sharing indemnified assets	75,500,000
Federal deposit insurance corporation loss-sharing indemnified assets receivable	7,600,000
FDIC Loss-sharing Asset, Period Increase (Decrease)	784,000
Covered Loans [Member]
Covered Assets And FDIC Loss Sharing Asset [Line Items]
Percentage of loss shared by FDIC	80.00%
FDIC Percentage Of Loss Recoveries	80.00%
Percentage of loss shared by FDIC When Loss Share Thresholds Met	95.00%
Percentage Of Loss Recoveries Shared By FDIC When Loss Share Thresholds Met	95.00%
Provision for loan and lease losses	980,000	15,685,000
Impairment expenses	1,300,000
Negative provision to adjust allowance for loss	$ 300,000
Covered Loans [Member] | Maximum [Member]
Covered Assets And FDIC Loss Sharing Asset [Line Items]
Loss Sharing Agreement Effective Years	10 years
Loss Recovery Provision Effective Years	10 years
Covered Loans [Member] | Minimum [Member]
Covered Assets And FDIC Loss Sharing Asset [Line Items]
Loss Sharing Agreement Effective Years	5 years
Loss Recovery Provision Effective Years	8 years