Borrowings and Borrowing Capacity - Summary of Customer Repurchase Agreements (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Debt Disclosure [Abstract]
Amount outstanding at end of period	$ 14,192	$ 2,033
Weighted average interest rate at end of period	0.03%	0.03%
Average daily balance during the period	$ 6,520	$ 7,823
Weighted average interest rate during the period	0.03%	0.02%
Maximum month-end balance during the period	$ 14,192	$ 14,463