Pension and Other Post-Retirement Benefit Plans (Funded Status) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Pension Plans [Member]
Change in benefit obligation [Roll Forward]
Service cost	$ 0	$ 0	$ 0	$ 0
Interest cost	5,597	6,970	16,791	20,910
Change in plan assets [Roll Forward]
Employer contributions			1,800
Post-Retirement Healthcare Plans [Member]
Change in benefit obligation [Roll Forward]
Service cost	24	35	72	104
Interest cost	$ 10	$ 23	$ 30	$ 68