Borrowed Funds - Short-term Borrowings, Long-term borrowings and Repurchase Agreements (Details) - USD ($)	6 Months Ended	12 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Borrowed funds
FHLB maximum borrowing capacity	$ 480,100,000
FHLB, remaining borrowing capacity	468,800,000
Paycheck Protection Program Liquidity Facility
Borrowed funds
Long-term debt	100,000	$ 0
Short-term Borrowings from FHLB
Short-term Borrowings and Repurchase Agreements
Balance at end of period	100,000	0
Average balance during the period	50,901,000	68,407,000
Maximum month-end balance	$ 130,047,000	$ 154,248,000
Weighted-average rate during the period	0.35%	0.58%
Weighted-average rate at end of period	0.33%	0.00%
Investment Securities
Short-term Borrowings and Repurchase Agreements
Investment securities held as collateral	$ 11,800,000	$ 10,700,000
Repurchase Agreements
Short-term Borrowings and Repurchase Agreements
Balance at end of period	11,361,000	10,266,000
Average balance during the period	10,542,000	9,856,000
Maximum month-end balance	$ 11,361,000	$ 10,505,000
Weighted-average rate during the period	0.15%	0.23%
Weighted-average rate at end of period	0.12%	0.14%