Employee Stock Ownership Plan - Additional Information (Detail) - USD ($) $ in Thousands		12 Months Ended
	May 12, 1998	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	May 01, 2018	Apr. 30, 2018
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Contributions to ESOP		$ 1,500	$ 1,400
Dividends paid unallocated ESOP shares		357	287
Outstanding loan		$ 9,300	$ 10,400
Unallocated shares of ESOP (shares)		459,711	525,241
Fair value of unallocated shares		$ 11,700
Shares allocated to participants (shares)		2,412,132
Shares committed to be released (shares)		65,531
Employee Stock Ownership Plan
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Minimum age limit for employees to participate in ESOP (years)		21 years
Minimum number of working hours (hours)		1000 hours
ESOP original borrowings		$ 13,400
Purchase of common stock shares (shares)		2,013,137
Additional borrowings	$ 8,200				$ 8,400
Additional common stock shares (shares)	633,750				292,592
Fixed interest rate (percent)					3.25%	8.25%
Compensation expense related to ESOP		$ 1,600	$ 1,600	$ 919
Increase in the average fair value		$ 366	$ 596	$ 637
Employee Stock Ownership Plan | Minimum
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Extended loan term (years)	12 years
Employee Stock Ownership Plan | Maximum
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Extended loan term (years)	30 years