Benefit Plans (Schedule of Net Benefit Costs) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Plan Disclosure [Line Items]
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	$ 34,044	$ 5,989	$ (16,786)
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	2,339	7,194	6,123
Interest cost	12,814	11,862	11,439
Expected return on assets	(14,938)	(12,136)	(13,313)
Prior service cost	(469)	(388)	(394)
Defined Benefit Plan, Amortization of Gains (Losses), prior to settlement/curtailment income	4,693	10,371	7,120
Curtailment gain	(524)	(142)	0
Defined Benefit Plan, Net Periodic Benefit Cost	4,852	17,537	11,763
Defined Benefit Plan, Actuarial Gain (Loss)	(47,417)	1,281	38,403
Cumulative net loss	(4,169)	(10,229)	(7,120)
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Tax	(52,054)	(9,337)	30,889
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	(47,203)	8,200	42,652
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	99	77	54
Interest cost	563	697	886
Expected return on assets	0	0	0
Prior service cost	(468)	(468)	0
Defined Benefit Plan, Amortization of Gains (Losses), prior to settlement/curtailment income	268	288	114
Curtailment gain	0	0	0
Defined Benefit Plan, Net Periodic Benefit Cost	462	594	1,054
Defined Benefit Plan, Actuarial Gain (Loss)	(682)	(57)	(3,217)
Cumulative net loss	(268)	(288)	(114)
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Tax	(482)	123	(3,330)
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	$ (20)	$ 717	$ (2,276)