Income Taxes - Net Deferred Tax Asset and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Allowance for loan losses	$ 542	$ 884
Deferred compensation	692	658
Accrued employee benefits	136	229
Loss carryforwards	4,743	4,080
Unrealized (gain) loss on available for sale securities	(39)	586
Premises and equipment	11	262
Other	14	91
Total deferred tax assets	6,099	6,790
Deferred tax liabilities:
Loan fees	82	136
Mortgage servicing rights	589	570
FHLB stock dividends	28	38
Total deferred tax liabilities	699	744
Net deferred tax asset	$ 5,400	$ 6,046