Summary of Significant Accounting Policies Narrative (Details) (USD $)	12 Months Ended
	Dec. 31, 2011 subsidiarytrusts	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2011 Building and Building Improvements [Member] years	Dec. 31, 2011 Furniture and Fixtures [Member] years	Dec. 31, 2011 Equipment [Member] years	Dec. 31, 2011 LIH Low Income Housing [Member]	Dec. 31, 2010 LIH Low Income Housing [Member]	Dec. 31, 2009 LIH Low Income Housing [Member]	Dec. 31, 2011 Other Assets [Member]	Dec. 31, 2010 Other Assets [Member]	Apr. 30, 2009 Scenario, Previously Reported [Member] Pooled Trust Preferred Securities [Member]	Dec. 31, 2011 FSP FAS 115-2 and FAS 124-2 [Member] Scenario, Previously Reported [Member] Pooled Trust Preferred Securities [Member]
Business [Abstract]
Number Of Subsidiary Trusts Owned By Parent	5
Investments [Abstract]
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net, Available-for-sale Securities												$ 9,700,000
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Debt Securities													6,300,000
Accumulated Other Comprehensive Income Loss Other Than Temporary Impairment Not Credit Loss Debt Security Tax													3,400,000
Loans and Revenue Recognition [Abstract]
Days Past Due For Nonaccrual Status	90 days
Premises and Equipment [Abstract]
Property, Plant and Equipment, Useful Life, Maximum				50	8	5
Disclosures about Segments of an Enterprise and Related Information [Abstract]
Number Of Banks Owned	6
Variable Interest Entity [Abstract]
Number Of Subsidiary Trusts Owned By Parent	5
Amortization Period Of LIH Investments	10 years
Investments, Low Income Housing										118,400,000	101,700,000
Income Tax Expense (Benefit)	$ 50,838,000	$ 44,409,000	$ 15,408,000				$ (8,500,000)	$ (5,700,000)	$ (4,700,000)
Number Of Banks Owned	6