Pension and Other Post-Retirement Benefit Plans (Funded Status) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Pension Plans [Member]
Change in benefit obligation [Roll Forward]
Service cost	$ 0	$ 0	$ 0	$ 0
Interest cost	7,825	7,284	23,474	21,852
Change in plan assets [Roll Forward]
Employer contributions			5,400
Post-Retirement Healthcare Plans [Member]
Change in benefit obligation [Roll Forward]
Service cost	27	30	81	90
Interest cost	$ 37	$ 32	$ 111	$ 96