Fair Value of Assets and Liabilities - Schedule of Assets Measured at Fair Value on a Non-Recurring Basis (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage servicing rights, fair value	$ 8,520	$ 2,981
Gains (losses) on assets held, foreclosed real estate		(100)
Gains (losses) on assets held, mortgage servicing rights	(390)	(34)
Gains (Losses) on assets held	(390)	(134)
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, Loans held for sale	30,452	2,931
Fair Value, Measurements, Nonrecurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage servicing rights, fair value	8,486	2,567
Assets, Fair Value Disclosure	8,486	5,437
Fair value, Loans held for sale		2,870
Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, Collateral dependent impaired loans	518	552
Fair value, Foreclosed real estate		500
Assets, Fair Value Disclosure	$ 518	$ 1,052