Fair Value (Reconciliation of all Assets Measured at Fair Value on Recurring Basis, Using Significant Unobservable Inputs (Level 3) (Details) - Fair Value, Measurements, Recurring - Significant Unobservable  Inputs (Level 3) - Obligations of State and Political Subdivisions - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance of Recurring Level 3 Assets at January 1	$ 497	$ 4,021
Total Losses Included in Other Comprehensive Income	(2)	(16)
Maturities / Calls	(495)	(523)
Purchases	0	0
Balance of Recurring Level 3 Assets at March 31	$ 0	$ 3,482