Tax Credit Investments Tax Credit Investments - Affordable Housing Tax Credit Investments, Other Tax Credit Investments, and Related Unfunded Commitments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Schedule of Equity Method Investments [Line Items]
Affordable housing tax credits and other tax benefits	$ 1,731	$ 1,393
Other tax credit investment credits and tax benefits	3,618	3,188
Total reduction in income tax expense	5,349	4,581
Other Assets [Member]
Other Assets [Abstract]
Affordable housing tax credit investments, net	34,843		36,009
Other tax credit investments, net	62,693		66,023
Total tax credit investments, net	97,536		102,032
Accrued Expenses And Other Liabilities [Member]
Other Liabilities [Abstract]
Unfunded affordable housing tax credit commitments	8,080		8,800
Unfunded other tax credit commitments	418		418
Total unfunded tax credit commitments	$ 8,498		$ 9,218