Mortgage Servicing Assets (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Gross carrying values, accumulated amortization, and net carrying values of mortgage servicing assets
Gain on sale of loans	$ 344,000	$ 0
Servicing Asset at Amortized Cost, Additions	344,000
Transfer to Investments	36,826,000
Proceeds from sale of mortgage loans on a servicing retained basis	2,200,000
Mortgage servicing assets
Balance at beginning of year	226,000	263,000
Additions	344,000
Impairments	(16,000)
Amortization	(51,000)	(37,000)
Balance at end of year	503,000	226,000
Gross carrying value	1,638,000	1,310,000
Accumulated amortization	(1,135,000)	(1,084,000)
Net carrying value	503,000	226,000
Estimated amortization expense
Net carrying value	503,000	226,000
Fair values and key assumptions used in determining the fair values of mortgage servicing assets
Fair value, beginning of year	291,000	311,000
Fair value, end of year	552,000	291,000
Annual cost to service (per loan, in dollars)	$ 75	$ 70
Weighted Average
Fair values and key assumptions used in determining the fair values of mortgage servicing assets
Discount rate (as a percent)	10.25%	10.50%
Weighted average prepayment speed assumption (CPR)	12.58%	8.86%
Mortgage-backed securities
Gross carrying values, accumulated amortization, and net carrying values of mortgage servicing assets
Transfer to Investments	$ 36,800,000
Mortgage Servicing Assets
Mortgage servicing assets
Net carrying value	503,000
Estimated amortization expense
2019	92,000
2020	73,000
2021	57,000
2022	46,000
2023	38,000
Thereafter	197,000
Net carrying value	$ 503,000