Fair Values of Financial Instruments - Reconciliation of Beginning and Ending Balances of Recurring Fair Value Measurements using Significant Unobservable Level 3 Inputs (Details) - Fair Value, Measurements, Recurring - Available for Sale Securities - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Available for Sale Securities
Beginning Balance	$ 3,328	$ 3,978
Included in other comprehensive income	80	(49)
Principal payments	(515)	(601)
Ending balance	$ 2,893	$ 3,328