Pension and Other Post-Retirement Benefit Plans (Funded Status) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Pension Plans [Member]
Change in benefit obligation [Roll Forward]
Service cost	$ 0	$ 0	$ 0	$ 0
Interest cost	5,597	6,970	11,194	13,940
Change in plan assets [Roll Forward]
Employer contributions			1,400
Post-Retirement Healthcare Plans [Member]
Change in benefit obligation [Roll Forward]
Service cost	24	35	48	69
Interest cost	$ 10	$ 23	$ 20	$ 45