Tax Credit Investments Tax Credit Investments - Affordable Housing Tax Credit Investments, Other Tax Credit Investments, and Related Unfunded Commitments (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Other Assets
Other Assets [Abstract]
Affordable housing tax credit investments, net	$ 33,514	$ 36,009
Other tax credit investments, net	54,872	66,023
Total tax credit investments, net	88,386	102,032
Other Liabilities
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