Fair Value Measurements (Details) (USD $) In Thousands, unless otherwise specified			12 Months Ended		12 Months Ended		12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 Convertible Senior Debentures, Due 2040 [Member]	Dec. 31, 2011 Convertible Senior Debentures, Due 2040 [Member]	Dec. 31, 2012 Convertible Senior Debentures, Due 2041 [Member]	Dec. 31, 2011 Convertible Senior Debentures, Due 2041 [Member]	Dec. 31, 2012 Convertible Senior Debentures 2042 [Member]	Dec. 31, 2012 U.S. Plans [Member]	Dec. 31, 2011 U.S. Plans [Member]	Dec. 31, 2010 U.S. Plans [Member]	Dec. 31, 2012 U.S. Plans [Member] Equity Securities [Member]	Dec. 31, 2011 U.S. Plans [Member] Equity Securities [Member]	Dec. 31, 2012 U.S. Plans [Member] Fixed Income Securities [Member]	Dec. 31, 2011 U.S. Plans [Member] Fixed Income Securities [Member]	Dec. 31, 2012 U.S. Plans [Member] Real Estate Investment Trust Securities [Member]	Dec. 31, 2011 U.S. Plans [Member] Real Estate Investment Trust Securities [Member]	Dec. 31, 2012 U.S. Plans [Member] Cash and Cash Equivalents [Member]	Dec. 31, 2011 U.S. Plans [Member] Cash and Cash Equivalents [Member]	Dec. 31, 2012 Non-U.S. Plans [Member]	Dec. 31, 2011 Non-U.S. Plans [Member]	Dec. 31, 2010 Non-U.S. Plans [Member]	Dec. 31, 2012 Non-U.S. Plans [Member] Equity Securities [Member]	Dec. 31, 2011 Non-U.S. Plans [Member] Equity Securities [Member]	Dec. 31, 2012 Non-U.S. Plans [Member] Fixed Income Securities [Member]	Dec. 31, 2011 Non-U.S. Plans [Member] Fixed Income Securities [Member]	Dec. 31, 2012 Non-U.S. Plans [Member] Cash and Cash Equivalents [Member]	Dec. 31, 2011 Non-U.S. Plans [Member] Cash and Cash Equivalents [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 1 [Member]	Dec. 31, 2011 Fair Value, Inputs, Level 1 [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 1 [Member] Convertible Senior Debentures, Due 2040 [Member]	Dec. 31, 2011 Fair Value, Inputs, Level 1 [Member] Convertible Senior Debentures, Due 2040 [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 1 [Member] Convertible Senior Debentures, Due 2041 [Member]	Dec. 31, 2011 Fair Value, Inputs, Level 1 [Member] Convertible Senior Debentures, Due 2041 [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 1 [Member] Convertible Senior Debentures 2042 [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 1 [Member] U.S. Plans [Member] Equity Securities [Member]	Dec. 31, 2011 Fair Value, Inputs, Level 1 [Member] U.S. Plans [Member] Equity Securities [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 1 [Member] U.S. Plans [Member] Fixed Income Securities [Member]	Dec. 31, 2011 Fair Value, Inputs, Level 1 [Member] U.S. Plans [Member] Fixed Income Securities [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 1 [Member] U.S. Plans [Member] Real Estate Investment Trust Securities [Member]	Dec. 31, 2011 Fair Value, Inputs, Level 1 [Member] U.S. Plans [Member] Real Estate Investment Trust Securities [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 1 [Member] U.S. Plans [Member] Cash and Cash Equivalents [Member]	Dec. 31, 2011 Fair Value, Inputs, Level 1 [Member] U.S. Plans [Member] Cash and Cash Equivalents [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 1 [Member] Non-U.S. Plans [Member] Equity Securities [Member]	Dec. 31, 2011 Fair Value, Inputs, Level 1 [Member] Non-U.S. Plans [Member] Equity Securities [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 1 [Member] Non-U.S. Plans [Member] Fixed Income Securities [Member]	Dec. 31, 2011 Fair Value, Inputs, Level 1 [Member] Non-U.S. Plans [Member] Fixed Income Securities [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 1 [Member] Non-U.S. Plans [Member] Cash and Cash Equivalents [Member]	Dec. 31, 2011 Fair Value, Inputs, Level 1 [Member] Non-U.S. Plans [Member] Cash and Cash Equivalents [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 2 [Member]	Dec. 31, 2011 Fair Value, Inputs, Level 2 [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 2 [Member] Convertible Senior Debentures, Due 2040 [Member]	Dec. 31, 2011 Fair Value, Inputs, Level 2 [Member] Convertible Senior Debentures, Due 2040 [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 2 [Member] Convertible Senior Debentures, Due 2041 [Member]	Dec. 31, 2011 Fair Value, Inputs, Level 2 [Member] Convertible Senior Debentures, Due 2041 [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 2 [Member] Convertible Senior Debentures 2042 [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 2 [Member] U.S. Plans [Member] Equity Securities [Member]	Dec. 31, 2011 Fair Value, Inputs, Level 2 [Member] U.S. Plans [Member] Equity Securities [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 2 [Member] U.S. Plans [Member] Fixed Income Securities [Member]	Dec. 31, 2011 Fair Value, Inputs, Level 2 [Member] U.S. Plans [Member] Fixed Income Securities [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 2 [Member] U.S. Plans [Member] Real Estate Investment Trust Securities [Member]	Dec. 31, 2011 Fair Value, Inputs, Level 2 [Member] U.S. Plans [Member] Real Estate Investment Trust Securities [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 2 [Member] U.S. Plans [Member] Cash and Cash Equivalents [Member]	Dec. 31, 2011 Fair Value, Inputs, Level 2 [Member] U.S. Plans [Member] Cash and Cash Equivalents [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 2 [Member] Non-U.S. Plans [Member] Equity Securities [Member]	Dec. 31, 2011 Fair Value, Inputs, Level 2 [Member] Non-U.S. Plans [Member] Equity Securities [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 2 [Member] Non-U.S. Plans [Member] Fixed Income Securities [Member]	Dec. 31, 2011 Fair Value, Inputs, Level 2 [Member] Non-U.S. Plans [Member] Fixed Income Securities [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 2 [Member] Non-U.S. Plans [Member] Cash and Cash Equivalents [Member]	Dec. 31, 2011 Fair Value, Inputs, Level 2 [Member] Non-U.S. Plans [Member] Cash and Cash Equivalents [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 3 [Member]	Dec. 31, 2011 Fair Value, Inputs, Level 3 [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 3 [Member] Convertible Senior Debentures, Due 2040 [Member]	Dec. 31, 2011 Fair Value, Inputs, Level 3 [Member] Convertible Senior Debentures, Due 2040 [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 3 [Member] Convertible Senior Debentures, Due 2041 [Member]	Dec. 31, 2011 Fair Value, Inputs, Level 3 [Member] Convertible Senior Debentures, Due 2041 [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 3 [Member] Convertible Senior Debentures 2042 [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 3 [Member] U.S. Plans [Member] Equity Securities [Member]	Dec. 31, 2011 Fair Value, Inputs, Level 3 [Member] U.S. Plans [Member] Equity Securities [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 3 [Member] U.S. Plans [Member] Fixed Income Securities [Member]	Dec. 31, 2011 Fair Value, Inputs, Level 3 [Member] U.S. Plans [Member] Fixed Income Securities [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 3 [Member] U.S. Plans [Member] Real Estate Investment Trust Securities [Member]	Dec. 31, 2011 Fair Value, Inputs, Level 3 [Member] U.S. Plans [Member] Real Estate Investment Trust Securities [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 3 [Member] U.S. Plans [Member] Cash and Cash Equivalents [Member]	Dec. 31, 2011 Fair Value, Inputs, Level 3 [Member] U.S. Plans [Member] Cash and Cash Equivalents [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 3 [Member] Non-U.S. Plans [Member] Equity Securities [Member]	Dec. 31, 2011 Fair Value, Inputs, Level 3 [Member] Non-U.S. Plans [Member] Equity Securities [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 3 [Member] Non-U.S. Plans [Member] Fixed Income Securities [Member]	Dec. 31, 2011 Fair Value, Inputs, Level 3 [Member] Non-U.S. Plans [Member] Fixed Income Securities [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 3 [Member] Non-U.S. Plans [Member] Cash and Cash Equivalents [Member]	Dec. 31, 2011 Fair Value, Inputs, Level 3 [Member] Non-U.S. Plans [Member] Cash and Cash Equivalents [Member]
Assets:
Assets held in rabbi trusts	$ 33,751	$ 31,698																										$ 21,954	$ 20,569																				$ 11,797	$ 11,129																				$ 0	$ 0
Fair value of plan assets								265,866	239,045	238,523	153,829	138,379	99,669	93,842	6,518	6,486	5,850	338	46,580	35,544	32,461	8,888	6,815	14,437	10,173	23,255	18,556								153,829	138,379	42,006	40,606	6,518	6,486	5,850	338	8,888	6,815	14,437	10,173	23,255	18,556								0	0	57,663	53,236	0	0	0	0	0	0	0	0	0	0								0	0	0	0	0	0	0	0	0	0	0	0	0	0
Available for sale securities	7,580	6,776																										7,580	6,776																				0	0																				0	0
Fair Value Assets	353,777	313,063																										284,317	248,698																				69,460	64,365																				0	0
Liabilities:
Embedded derivative	(1,303)	(986)	(622)	(594)	(399)	(392)	(282)																					0	0	0	0	0	0	0															0	0	0	0	0	0	0															(1,303)	(986)	(622)	(594)	(399)	(392)	(282)
Long-term Debt, Fair Value	686,800	533,900
Convertible debentures issuance date			Nov. 09, 2010		May 13, 2011		May 31, 2012
Long-term Debt	$ 391,628	$ 398,068