Allowance for Loan Losses - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2017	Dec. 31, 2016	Jul. 01, 2006
Receivables [Abstract]
Period of forbearance within twenty-four month period to be classified as TDR (more than)	3 months
Period after grace period for forbearance allowance	9 months
Forbearance period after grace period	6 months
Percentage of loans granted forbearance qualified as TDR	26.00%	26.00%
Criteria for loans to be considered as nonperforming	90 days
Tier 1 of government guarantee (at least) (in percentage)	97.00%		97.00%
TDR payment default period	60 days
Period of loans past due that have accrued interest	90 days