Fair Value Measurements (Details 3)	12 Months Ended
	Dec. 31, 2019 USD ($) item	Dec. 31, 2018 USD ($) item
Changes in the fair value of Level 3 assets measured on a recurring basis
Total gains or losses (unrealized): included in earnings	$ 0	$ 0
Number of transfers between Level 1 and Level 2 | item	0	0
Number of transfers between Level 2 and Level 3 | item	0	1
U.S. States and political subdivisions securities
Changes in the fair value of Level 3 assets measured on a recurring basis
Balance at the beginning of the period	$ 1,025,000	$ 2,155,000
Total gains or losses (realized/unrealized): included in earnings	0	0
Total gains or losses (realized/unrealized): included in other comprehensive income	(35,000)	6,000
Purchases	5,600,000	0
Issuances	0	0
Sales	0	0
Settlements	0	0
Maturities	(4,298,000)	(1,136,000)
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Balance at the end of the period	2,292,000	1,025,000
Foreign government and other securities
Changes in the fair value of Level 3 assets measured on a recurring basis
Balance at the beginning of the period	0	710,000
Total gains or losses (realized/unrealized): included in earnings	0	0
Total gains or losses (realized/unrealized): included in other comprehensive income	0	(11,000)
Purchases	0	200,000
Issuances	0	0
Sales	0	0
Settlements	0	0
Maturities	0	(200,000)
Transfers into Level 3	0	0
Transfers out of Level 3	0	(699,000)
Balance at the end of the period	0	0
Investment securities available-for-sale
Changes in the fair value of Level 3 assets measured on a recurring basis
Balance at the beginning of the period	1,025,000	2,865,000
Total gains or losses (realized/unrealized): included in earnings	0	0
Total gains or losses (realized/unrealized): included in other comprehensive income	(35,000)	(5,000)
Purchases	5,600,000	200,000
Issuances	0	0
Sales	0	0
Settlements	0	0
Maturities	(4,298,000)	(1,336,000)
Transfers into Level 3	0	0
Transfers out of Level 3	0	(699,000)
Balance at the end of the period	$ 2,292,000	$ 1,025,000