Pension and Other Postretirement Benefits (Impact on Amounts Reported Due to a 1% Change in the Annual Medical Inflation Rate Issued) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Other Postretirement Benefits [Abstract]
Effect on accumulated postretirement benefit obligation, 1% increase	$ 716	$ 831
Effect on accumulated postretirement benefit obligation, 1% decrease	(614)	(702)
Effect on annual service and interest costs, 1% increase	31	36
Effect on annual service and interest costs, 1% decrease	$ (26)	$ (30)