Employee Benefit Plans (Components of Net Periodic Postretirement Benefit Costs and Other Amounts Recognized in OCI) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Changes in postretirement benefit obligation recognized in other comprehensive income:
Total pre-tax changes in postretirement benefit obligation recognized in other comprehensive income	$ (227)	$ 121	$ (422)
Health Insurance Postretirement Benefit
Net periodic benefit expense:
Service cost	54	70	49
Interest cost	60	59	43
Prior service credit	(21)	(21)	(21)
Actuarial gain	(27)	0	(47)
Net periodic benefit expense	66	108	24
Changes in postretirement benefit obligation recognized in other comprehensive income:
Net actuarial (loss) gain	(206)	142	(401)
Prior service credit	(21)	(21)	(21)
Total pre-tax changes in postretirement benefit obligation recognized in other comprehensive income	$ (227)	$ 121	$ (422)