Pension and Other Post-Retirement Benefit Plans (Net Periodic Benefit Costs) (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]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	$ 0	$ 0	$ 0	$ 0
Interest cost	8,646	9,879	17,292	19,758
Expected return on plan assets	(11,020)	(11,528)	(22,040)	(23,056)
Amortization of prior service cost	0	0	0	0
Amortization of net (gain) loss	1,793	0	3,586	(1)
Net periodic benefit cost (gain)	(581)	(1,649)	(1,162)	(3,299)
Post-Retirement Healthcare Plans [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	44	60	88	120
Interest cost	48	71	96	142
Expected return on plan assets	0	0	0	0
Amortization of prior service cost	(136)	(872)	(272)	(1,744)
Amortization of net (gain) loss	73	80	146	160
Net periodic benefit cost (gain)	$ 29	$ (661)	$ 58	$ (1,322)