Accumulated Other Comprehensive Loss (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Summary of components of accumulated other comprehensive loss, net of tax
Currency Translation Adjustment, Beginning Balance	$ 28,219	$ 45,987	$ 32,978
Net Actuarial Loss, Beginning Balance	(599,687)	(428,532)	(419,445)
Prior Service Credit, Beginning Balance	4,291	5,912	7,482
Transition Obligation, Beginning Balance	12	34	52
Unrealized (Loss) Gain on Derivatives, Beginning Balance	0	0	14
Accumulated other comprehensive loss, Beginning Balance	(567,165)	(376,599)	(378,919)
Amortization of Net Actuarial Loss	20,315	13,146	12,416
Amortization of Prior Service Credit	(1,657)	(1,621)	(1,570)
Amortization of Transition Obligation	0	(22)	(18)
Amortization of Accumulated Other Comprehensive Loss	18,658	11,503	10,828
Pension curtailment/ settlement, Net Actuarial Loss			1,074
Pension curtailment/settlement, Prior Service Credit			0
Pension curtailment/settlement, Accumulated Other Comprehensive Loss			1,074
Current period change, Currency Translation Adjustments	29,629	(17,768)	13,009
Current period change, Net Actuarial Loss	(68,753)	(184,301)	(22,577)
Current period change, Unrealized Gain (Loss) on Derivatives	12	0	(14)
Current period change, Accumulated Other Comprehensive Loss	(39,112)	(202,069)	(9,582)
Currency Translation Adjustment, Ending Balance	57,848	28,219	45,987
Net Actuarial Loss, Ending Balance	(648,125)	(599,687)	(428,532)
Prior Service Credit, Ending Balance	2,634	4,291	5,912
Transition Obligation, Ending Balance	12	12	34
Unrealized (Loss) Gain on Derivatives, Ending Balance	12	0	0
Accumulated other comprehensive loss, Ending Balance	$ (587,619)	$ (567,165)	$ (376,599)