Premises and Equipment, Net (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Property, Plant and Equipment [Line Items]
Premises and equipment before accumulated depreciation	$ 151,120,000	$ 168,638,000
Accumulated depreciation	76,579,000	101,234,000
Total premises and equipment	74,541,000	67,404,000
Rental expense	5,900,000	5,500,000	5,300,000
Operating Leases, Future Minimum Payments Due [Abstract]
2012	5,337,000
2013	5,200,000
2014	4,786,000
2015	4,365,000
2016	4,121,000
Thereafter	25,081,000
Total	48,890,000
Depreciated asset removal	27,100,000
Land, Buildings and Improvements [Member]
Property, Plant and Equipment [Line Items]
Premises and equipment before accumulated depreciation	103,399,000	95,970,000
Pledged to secure long-term borrowings	2,900,000	3,000,000
Equipment [Member]
Property, Plant and Equipment [Line Items]
Premises and equipment before accumulated depreciation	47,646,000	72,326,000
Property, Plant and Equipment, Useful Life, Minimum (in years)	3
Property, Plant and Equipment, Useful Life, Maximum (in years)	10
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Premises and equipment before accumulated depreciation	$ 75,000	$ 342,000
Building and Building Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life, Minimum (in years)	15
Property, Plant and Equipment, Useful Life, Maximum (in years)	40