Goodwill and Other Intangible Assets (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Goodwill [Roll Forward]
Beginning Balance	$ 114,841,000	$ 114,938,000
Goodwill Acquired	17,188,000	0
Goodwill Reclassification	0	(97,000)
Ending Balance	132,029,000	114,841,000	114,938,000
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	32,885,000	29,318,000
Less: accumulated amortization	14,691,000	11,775,000
Net carrying amount	18,194,000	17,543,000
Finite-Lived Intangible Assets, Future Amortization Expense [Abstract]
Intangible assets estimated useful lives, minimum (in years)	1
Intangible assets estimated useful lives, maximum (in years)	12
Amortization expense on intangible assets with definite useful lives	3,000,000	3,100,000	3,200,000
2012	3,200,000
2013	3,000,000
2014	2,800,000
2015	2,600,000
2016	1,600,000
Thereafter	3,000,000
Indefinite-Lived Intangible Assets (Excluding Goodwill)	2,000,000
Core Deposits [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	11,966,000	10,762,000
Less: accumulated amortization	6,401,000	5,517,000
Net carrying amount	5,565,000	5,245,000
Other Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	20,919,000	18,556,000
Less: accumulated amortization	8,290,000	6,258,000
Net carrying amount	$ 12,629,000	$ 12,298,000