Loans and Asset Quality Information (Details 3) (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
Covered purchased nonimpaired loans:
Carrying amount of nonimpaired covered loans, beginning balance	$ 277,489	$ 353,370
Principal repayments	(49,793)	(51,582)
Transfers to foreclosed real estate	(9,529)	(30,181)
Loan charge-offs	(9,000)	(10,584)
Accretion of loan discount	14,595	16,466
Balance, ending, carrying value	$ 223,762	$ 277,489