Fair Value Measurements (Details) (USD $) In Thousands, unless otherwise specified			12 Months Ended		12 Months Ended		12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013 Convertible Senior Debentures, Due 2040 [Member]	Dec. 31, 2012 Convertible Senior Debentures, Due 2040 [Member]	Dec. 31, 2013 Convertible Senior Debentures, Due 2041 [Member]	Dec. 31, 2012 Convertible Senior Debentures, Due 2041 [Member]	Dec. 31, 2013 Convertible Senior Debentures 2042 [Member]	Dec. 31, 2013 U.S. Plans [Member]	Dec. 31, 2012 U.S. Plans [Member]	Dec. 31, 2011 U.S. Plans [Member]	Dec. 31, 2013 U.S. Plans [Member] Equity Securities [Member]	Dec. 31, 2012 U.S. Plans [Member] Equity Securities [Member]	Dec. 31, 2013 U.S. Plans [Member] Fixed Income Securities [Member]	Dec. 31, 2012 U.S. Plans [Member] Fixed Income Securities [Member]	Dec. 31, 2013 U.S. Plans [Member] Real Estate Investment Trust Securities [Member]	Dec. 31, 2012 U.S. Plans [Member] Real Estate Investment Trust Securities [Member]	Dec. 31, 2013 U.S. Plans [Member] Cash and Cash Equivalents [Member]	Dec. 31, 2012 U.S. Plans [Member] Cash and Cash Equivalents [Member]	Dec. 31, 2013 Non-U.S. Plans [Member]	Dec. 31, 2012 Non-U.S. Plans [Member]	Dec. 31, 2011 Non-U.S. Plans [Member]	Dec. 31, 2013 Non-U.S. Plans [Member] Equity Securities [Member]	Dec. 31, 2012 Non-U.S. Plans [Member] Equity Securities [Member]	Dec. 31, 2013 Non-U.S. Plans [Member] Fixed Income Securities [Member]	Dec. 31, 2012 Non-U.S. Plans [Member] Fixed Income Securities [Member]	Dec. 31, 2013 Non-U.S. Plans [Member] Cash and Cash Equivalents [Member]	Dec. 31, 2012 Non-U.S. Plans [Member] Cash and Cash Equivalents [Member]	Dec. 31, 2013 Fair Value, Inputs, Level 1 [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 1 [Member]	Dec. 31, 2013 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] Equity Securities [Member]	Dec. 31, 2013 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] Fixed Income Securities [Member]	Dec. 31, 2013 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] Real Estate Investment Trust Securities [Member]	Dec. 31, 2013 Fair Value, Inputs, Level 1 [Member] U.S. Plans [Member] Cash and Cash Equivalents [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 1 [Member] U.S. Plans [Member] Cash and Cash Equivalents [Member]	Dec. 31, 2013 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] Equity Securities [Member]	Dec. 31, 2013 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] Fixed Income Securities [Member]	Dec. 31, 2013 Fair Value, Inputs, Level 1 [Member] Non-U.S. Plans [Member] Cash and Cash Equivalents [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 1 [Member] Non-U.S. Plans [Member] Cash and Cash Equivalents [Member]	Dec. 31, 2013 Fair Value, Inputs, Level 2 [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 2 [Member]	Dec. 31, 2013 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] Equity Securities [Member]	Dec. 31, 2013 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] Fixed Income Securities [Member]	Dec. 31, 2013 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] Real Estate Investment Trust Securities [Member]	Dec. 31, 2013 Fair Value, Inputs, Level 2 [Member] U.S. Plans [Member] Cash and Cash Equivalents [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 2 [Member] U.S. Plans [Member] Cash and Cash Equivalents [Member]	Dec. 31, 2013 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] Equity Securities [Member]	Dec. 31, 2013 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] Fixed Income Securities [Member]	Dec. 31, 2013 Fair Value, Inputs, Level 2 [Member] Non-U.S. Plans [Member] Cash and Cash Equivalents [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 2 [Member] Non-U.S. Plans [Member] Cash and Cash Equivalents [Member]	Dec. 31, 2013 Fair Value, Inputs, Level 3 [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 3 [Member]	Dec. 31, 2013 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] Equity Securities [Member]	Dec. 31, 2013 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] Fixed Income Securities [Member]	Dec. 31, 2013 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] Real Estate Investment Trust Securities [Member]	Dec. 31, 2013 Fair Value, Inputs, Level 3 [Member] U.S. Plans [Member] Cash and Cash Equivalents [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 3 [Member] U.S. Plans [Member] Cash and Cash Equivalents [Member]	Dec. 31, 2013 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] Equity Securities [Member]	Dec. 31, 2013 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] Fixed Income Securities [Member]	Dec. 31, 2013 Fair Value, Inputs, Level 3 [Member] Non-U.S. Plans [Member] Cash and Cash Equivalents [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 3 [Member] Non-U.S. Plans [Member] Cash and Cash Equivalents [Member]
Assets:
Assets held in rabbi trusts	$ 36,992	$ 33,751																										$ 24,064	$ 21,954															$ 12,928	$ 11,797															$ 0	$ 0
Fair value of plan assets								295,633	265,866	239,045	51,666	153,829	241,827	99,669	1,969	6,518	171	5,850	48,859	46,580	35,544	9,911	8,888	16,117	14,437	22,831	23,255			51,666	153,829	194,777	42,006	1,969	6,518	171	5,850	9,911	8,888	16,117	14,437	22,831	23,255			0	0	47,050	57,663	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	7,356	7,580																										7,356	7,580															0	0															0	0
Fair Value Assets	388,840	353,777																										328,862	284,317															59,978	69,460															0	0
Liabilities:
Embedded derivative - convertible debentures due 2040	(491)	(622)																										0	0															0	0															(491)	(622)
Embedded derivative - convertible debentures due 2041	(349)	(399)																										0	0															0	0															(349)	(399)
Embedded derivative - convertible debentures due 2042	(197)	(282)																										0	0															0	0															(197)	(282)
Embedded derivatives total	(1,037)	(1,303)	(491)	(622)	(349)	(399)																						0	0															0	0															(1,037)	(1,303)
Long-term Debt, Fair Value	750,700	686,800
Convertible debentures issuance date			Nov. 09, 2010		May 13, 2011		May 31, 2012
Long-term Debt	$ 363,874	$ 391,628