Fair Value Measurements - Financial Assets and Liabilities Measured at Fair Value on Nonrecurring Basis (Detail) - Nonrecurring - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Assets
Impaired loans	$ 63,145	$ 65,914
OREO, net	8,875	6,433
Total	72,020	72,347
Level 1
Assets
Impaired loans	0	0
OREO, net	0	0
Total	0	0
Level 2
Assets
Impaired loans	0	0
OREO, net	0	0
Total	0	0
Level 3
Assets
Impaired loans	63,145	65,914
OREO, net	8,875	6,433
Total	$ 72,020	$ 72,347