Tax Credit Investments - Balance Sheet Disclosures (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Other Assets
Other Assets
Affordable housing tax credit investments, net	$ 40,568	$ 22,135
Other tax credit investments, net	35,976	42,015
Total tax credit investments, net	76,544	64,150
Other Liabilities
Other Liabilities
Unfunded affordable housing tax credit commitments	5,256	3,690
Unfunded other tax credit commitments	12,682	15,020
Total unfunded tax credit commitments	$ 17,938	$ 18,710