Goodwill and Intangible Assets - Schedule of Mortgage Servicing Rights (MSRs) and Related Valuation Allowance (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Loan Servicing Rights:
Balance at Beginning of Period	$ 1,717	$ 1,642	$ 1,562	$ 1,664
Additions	381	71	924	144
Amortized to expense	(135)	(81)	(361)	(176)
Change in valuation allowance	25		(137)
Balance at End of Period	1,988	$ 1,632	1,988	$ 1,632
Valuation allowance:
Balance at Beginning of Period	264		102
Additions expensed			162
Reductions credited to operations	(25)		(25)
Balance at End of Period	$ 239		$ 239