Short-Term and Other Borrowings - Summary of Federal Funds Purchased and Other Short-term Borrowings are Included in Short-term Federal Home Loan Bank Advances on Consolidated Balance Sheets (Detail) - USD ($)	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
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]
Outstanding balance		$ 121,300,000
Interest rate on balance		2.46%
Maximum indebtedness	$ 102,700,000	$ 192,700,000
Average balance	$ 16,391,000	$ 102,108,000
Average rate paid	1.64%	2.51%