Fair Value Measurements - Financial Assets and Liabilities Measured at Fair Value on Nonrecurring Basis (Detail) - Nonrecurring - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Assets
Loans	$ 71,748	$ 71,210
OREO, net	1,721	3,029
Total	73,469	74,239
Level 1
Assets
Loans	0	0
OREO, net	0	0
Total	0	0
Level 2
Assets
Loans	0	0
OREO, net	0	0
Total	0	0
Level 3
Assets
Loans	71,748	71,210
OREO, net	1,721	3,029
Total	$ 73,469	$ 74,239