Income Taxes - Schedule of Significant Portions of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Allowance for loan losses	$ 3,501	$ 3,311
Reserve for repurchased loans	55	97
Reserve for uncollected interest	119	49
Incentive compensation	1,302	0
Deferred compensation	529	519
Other reserves	334	115
Stock plans	950	864
ESOP	142	126
Purchase accounting adjustments	59,110	3,436
Net operating loss carryforward related to acquisition	2,736	3,741
Other real estate owned	90	170
Unrealized loss on securities	1,225	1,898
Total gross deferred tax assets	71,503	16,777
Deferred tax liabilities:
Incentive compensation	0	(127)
Excess servicing on sale of mortgage loans	(18)	(28)
Investments, discount accretion	(232)	(244)
Deferred loan and commitment costs, net	(1,478)	(1,119)
Premises and equipment, differences in depreciation	(4,350)	(373)
Undistributed REIT income	(1,730)	(12,322)
Other	(318)	(642)
Total gross deferred tax liabilities	(8,126)	(14,855)
Net deferred tax assets	63,377	1,922
Domestic Tax Authority
Deferred tax assets:
Federal and state alternative minimum tax	$ 1,410	$ 2,451