Pension and Other Post-Retirement Benefit Plans (Funded Status) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Pension Plans [Member]
Change in benefit obligation [Roll Forward]
Service cost	$ 0	$ 0	$ 0	$ 0
Interest cost	8,646	9,879	17,292	19,758
Change in plan assets [Roll Forward]
Employer contributions	291		935
Post-Retirement Healthcare Plans [Member]
Change in benefit obligation [Roll Forward]
Service cost	44	60	88	120
Interest cost	$ 48	$ 71	$ 96	$ 142