Pension and Other Post-Retirement Benefit Plans (Net Periodic Benefit Costs) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Pension Plans [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	$ 0	$ 0	$ 0	$ 0
Interest cost	8,989	9,272	17,978	18,544
Expected return on plan assets	(11,498)	(9,970)	(22,996)	(19,940)
Amortization of prior service cost	0	0	0	0
Amortization of net (gain) loss	3,074	2,670	6,148	5,340
Net periodic benefit cost (benefit)	565	1,972	1,130	3,944
Post-Retirement Healthcare Plan [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	69	67	138	134
Interest cost	66	95	132	190
Expected return on plan assets	0	0	0	0
Amortization of prior service cost	(1,413)	(1,387)	(2,826)	(2,774)
Amortization of net (gain) loss	104	108	208	216
Net periodic benefit cost (benefit)	$ (1,174)	$ (1,117)	$ (2,348)	$ (2,234)