Loans - Summary of Loans by Class Modified (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2020 USD ($) SecurityLoan	Mar. 31, 2019 USD ($) SecurityLoan
Mortgage Loans On Real Estate [Line Items]
Number of loans | SecurityLoan	3	1
Recorded investment | $	$ 497	$ 122
Residential Real Estate [Member]
Mortgage Loans On Real Estate [Line Items]
Number of loans | SecurityLoan	1
Recorded investment | $	$ 169
Commercial Real Estate [Member]
Mortgage Loans On Real Estate [Line Items]
Number of loans | SecurityLoan	1
Recorded investment | $	$ 267
Commercial and Industrial [Member]
Mortgage Loans On Real Estate [Line Items]
Number of loans | SecurityLoan	1	1
Recorded investment | $	$ 61	$ 122