Low Income Housing Tax Credits - Additional Information (Detail) - Housing Equity Funds $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2017 USD ($)	Jun. 30, 2017 USD ($) Investment
Schedule of Equity Method Investments [Line Items]
Number of investments in housing equity funds | Investment		3
Affordable housing investments and related tax benefits term		2029
Tax credits and other tax benefits recognized related to investments	$ 19	$ 45
Total projected tax credits to be received from investments	89	89
Other assets
Schedule of Equity Method Investments [Line Items]
Investments in housing equity funds	1,500	1,500
Other Liabilities
Schedule of Equity Method Investments [Line Items]
Additional capital calls expected for the fund	$ 1,500	$ 1,500