Investments - Amortized Cost and Fair Value of Investments Available-for-Sale by Contractual Maturity (Details) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Amortized Cost
Due within one year	$ 1,182,000
Due after one year through five years	260,000
Due after five years through ten years	458,000
Due after ten years	3,292,000
Mortgage-backed securities	3,642,000
Amortized Cost	8,834,000		$ 9,915,000
Fair Value
Due within one year	1,188,000
Due after one year through five years	271,000
Due after five years through ten years	499,000
Due after ten years	3,401,000
Mortgage-backed securities	3,719,000
Estimated Fair Value	9,078,000		10,218,000
Pledged securities	0		$ 0
Sales of available for sale securities	$ 0	$ 0