Fair Value (Reconciliation of all Assets Measured at Fair Value on Recurring Basis, Using Significant Unobservable Inputs (Level 3) (Details) - Fair Value, Measurements, Recurring - Obligations of State and Political Subdivisions - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance of Recurring Level 3 at Beginning of Period	$ 4,512	$ 5,171	$ 4,991	$ 5,649
Total Gains or Losses Included in Other Comprehensive Income	(6)	(4)	(15)	(22)
Maturities / Calls	0	0	(470)	(460)
Purchases	0	0	0	0
Balance of Recurring Level 3 Assets at End of Period	$ 4,506	$ 5,167	$ 4,506	$ 5,167