Financial Instruments with Off-Balance-Sheet Risk - (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Financial Instruments with Off-Balance-Sheet Risk
Loans sold to investors	$ 9,300,000
Mortgage loan sold, recourse period from date of sale	4 months
Mortgage loan sold, continuous default period	90 days
Mortgage loan sold, prepayment period	180 days
Indemnification amount in addition to service lease premium	$ 5,000
Recourse for number of days after date of sale	180 days
Loan origination commitments
Financial Instruments with Off-Balance-Sheet Risk
Off-balance-sheet risk, amount, liability	$ 524,000	$ 793,000