Covered Assets and FDIC Loss-sharing Asset (FDIC Loss-sharing Asset) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Covered Assets And FDIC Loss Sharing Asset
Balance at beginning of period	$ 96,354	$ 175,071
Cash received from the FDIC	(3,119)	(14,804)
FDIC reimbursable losses, net	363	462
Amortization, net	(9,779)	(13,873)
Impairment	784	12,548
Sale of other real estate	(1,346)	(2,067)
Write-downs of other real estate	52	1,629
Other	(194)	95
Balance at end of period	$ 83,115	$ 159,061