Servicing - Summary of Mortgage Servicing Rights Capitalized and Amortized (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Servicing Assets at Fair Value [Line Items]
Beginning of Year	$ 2,629
End of Year	3,320	$ 2,629
Mortgage Servicing Rights [Member]
Servicing Assets at Fair Value [Line Items]
Beginning of Year	2,629	2,385
Capitalized Additions	1,722	731
Amortization	(1,031)	(487)
Valuation Allowance	0	0
End of Year	$ 3,320	$ 2,629