Accumulated Other Comprehensive Loss (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Accumulated Other Comprehensive (Loss) [Roll Forward]
Accumulated other comprehensive loss, beginning of period	$ (587,619)	$ (567,165)
Amortization	10,817	9,293
Current period change	(53,657)	3,316
Accumulated other comprehensive loss, end of period	(630,459)	(554,556)
Currency Translation Adjustments
Accumulated Other Comprehensive (Loss) [Roll Forward]
Accumulated other comprehensive loss, beginning of period	57,848	28,219
Current period change	(49,952)	5,844
Accumulated other comprehensive loss, end of period	7,896	34,063
Net Actuarial Loss
Accumulated Other Comprehensive (Loss) [Roll Forward]
Accumulated other comprehensive loss, beginning of period	(648,125)	(599,687)
Amortization	11,514	10,107
Current period change	(3,714)	(2,547)
Accumulated other comprehensive loss, end of period	(640,325)	(592,127)
Prior Service Credit
Accumulated Other Comprehensive (Loss) [Roll Forward]
Accumulated other comprehensive loss, beginning of period	2,634	4,291
Amortization	(697)	(814)
Current period change	0	0
Accumulated other comprehensive loss, end of period	1,937	3,477
Transition Obligation
Accumulated Other Comprehensive (Loss) [Roll Forward]
Accumulated other comprehensive loss, beginning of period	12	12
Amortization	0	0
Current period change	0	0
Accumulated other comprehensive loss, end of period	12	12
Unrealized Gain (Loss) on Derivatives
Accumulated Other Comprehensive (Loss) [Roll Forward]
Accumulated other comprehensive loss, beginning of period	12	0
Amortization	0	0
Current period change	9	19
Accumulated other comprehensive loss, end of period	$ 21	$ 19