Benefit Plans (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended			3 Months Ended		9 Months Ended			3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Jul. 31, 2013	Sep. 30, 2013 Pension Benefits [Member]	Sep. 30, 2012 Pension Benefits [Member]	Sep. 30, 2013 Pension Benefits [Member]		Sep. 30, 2012 Pension Benefits [Member]	Sep. 30, 2013 Other Benefits [Member]	Sep. 30, 2012 Other Benefits [Member]	Sep. 30, 2013 Other Benefits [Member]	Sep. 30, 2012 Other Benefits [Member]
Components of net periodic benefit cost
Service cost				$ 2,647	$ 2,862	$ 9,308		$ 8,585	$ 0	$ 0	$ 0	$ 0
Interest cost				6,865	7,957	20,778		23,873	157	204	471	611
Expected return on plan assets				(9,017)	(10,205)	(26,622)		(30,616)	0	0	0	0
Amortization of prior service (benefit) cost				(136)	65	(99)		194	(122)	(130)	(366)	(388)
Recognized net actuarial loss				2,529	4,207	13,385		12,601	105	123	317	366
Curtailment loss (1)				809	0	1,968	[1]	0	0	0	0	0
Net periodic pension benefit cost				3,697	4,886	18,718		14,637	140	197	422	589
Defined Benefit Plan, Curtailments				52,462
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate			5.06%
Defined Benefit Plan, Actuarial Gain (Loss)				71,000
Defined Benefit Plan, Estimated Future Employer Contributions in Current Fiscal Year	0
Contributions to qualified and non qualified pension plans	$ 2,662	$ 14,915

[1] The curtailment recognized during the nine months ended September 30, 2013 resulted from the departure of certain executive officers and the U.S. salary plan benefit freeze and was recorded within selling and administrative expense.