Noninterest Expense (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Noninterest Expense [Abstract]
Employee compensation and benefits	$ 45,636	$ 43,828	$ 139,502	$ 129,514
OREO operations	4,008	10,739	9,337	36,591
Occupancy and equipment	11,034	9,580	32,253	29,558
Data processing	7,137	5,651	20,600	18,339
FDIC insurance	2,159	3,510	6,005	10,903
Professional Fees	4,929	3,161	12,718	9,571
Depreciation	2,918	3,000	8,754	9,026
Advertising	3,442	1,932	10,370	6,659
Travel and entertainment	1,420	1,336	4,019	3,931
Merger and acquisition	1,584	0	9,981	0
Amortization of other intangible assets	1,792	1,190	4,988	3,639
Other	3,349	2,693	7,137	8,784
Total noninterest expense	$ 89,408	$ 86,620	$ 265,664	$ 266,515