FDIC Indemnification Asset (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended		12 Months Ended
	Sep. 30, 2012		Dec. 31, 2011
FDIC Indemnification Asset [Abstract]
FDIC True-up provisions	$ 961		$ 601
Balance, beginning of period	28,348		0
Additions from acquisition			33,333
Accretion	187		185
Transfers to FDIC claims receivable	(1,271)
Loss-share payments received from FDIC			(986)
Change in expected cash flows	(2,925)	[1]	(4,157)	[1]
Change in FDIC true-up provision	(360)		(27)
Balance, end of period	$ 23,979		$ 28,348

[1] The decrease was due to loan pay-offs, improved cash flow projections, and lower loss expectations for covered loans.