Short-Term and Other Borrowings - Summary of Federal Funds Purchased, Securities Sold Under Agreements to Repurchase and Other Short-term Borrowings (Detail) - USD ($)	3 Months Ended	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2020
Federal Funds Purchased [Member]
Short-term Debt [Line Items]
Maximum indebtedness		$ 37,000,000
Average balance		$ 305,000
Average rate paid		1.98%
Short Term Borrowings, FHLB advances [Member]
Short-term Debt [Line Items]
Maximum indebtedness	$ 3,100,000	$ 102,700,000
Average balance	$ 34,000	$ 16,391,000
Average rate paid	0.30%	1.64%