Indebtedness (Narrative) (Details)									9 Months Ended	3 Months Ended		9 Months Ended									9 Months Ended
	Sep. 30, 2012 USD ($)	Dec. 31, 2011 USD ($)	Sep. 30, 2012 Interest Accrual, Option Two [Member]	Sep. 30, 2012 Interest Accrual, Option Three [Member]	Sep. 30, 2012 Minimum [Member]	Sep. 30, 2012 Minimum [Member] Interest Accrual, Option Three [Member] Variable Basis, Additional Margin [Member]	Sep. 30, 2012 Maximum [Member]	Sep. 30, 2012 Maximum [Member] Interest Accrual, Option Three [Member] Variable Basis, Additional Margin [Member]	Sep. 30, 2012 Conversion Event, One [Member] D	Sep. 30, 2012 1 1/4% Convertible Senior Subordinated Notes Due December 15, 2036 [Member] USD ($)	Sep. 30, 2011 1 1/4% Convertible Senior Subordinated Notes Due December 15, 2036 [Member] USD ($)	Sep. 30, 2012 1 1/4% Convertible Senior Subordinated Notes Due December 15, 2036 [Member] USD ($)	Sep. 30, 2011 1 1/4% Convertible Senior Subordinated Notes Due December 15, 2036 [Member] USD ($)	Dec. 31, 2011 1 1/4% Convertible Senior Subordinated Notes Due December 15, 2036 [Member] USD ($)	Sep. 30, 2012 4 1/2% Senior Unsecured Term Loan Due May 2, 2016 [Member] USD ($)	Sep. 30, 2012 4 1/2% Senior Unsecured Term Loan Due May 2, 2016 [Member] EUR (€)	Dec. 31, 2011 4 1/2% Senior Unsecured Term Loan Due May 2, 2016 [Member] USD ($)	Sep. 30, 2012 5 7/8% Senior Notes due 2021 [Member] USD ($)	Dec. 31, 2011 5 7/8% Senior Notes due 2021 [Member] USD ($)	Sep. 30, 2012 Multi-currency Revolving Credit Facility [Member] USD ($)	Sep. 30, 2012 Term Loan Facility [Member] USD ($)	Sep. 30, 2012 Term Loan Facility [Member] Future Periodic Payment [Member] USD ($)
Debt Instrument [Line Items]
Debt instrument, face amount										$ 201,300,000		$ 201,300,000		$ 201,300,000	$ 257,100,000	€ 200,000,000		$ 300,000,000
Interest expense on the liability component of convertible debt										2,800,000	2,700,000	8,400,000	8,100,000
Effective interest rate												6.10%	6.10%
Debt instrument, discount amortization period												December 2013
Debt maturity date												Dec. 15, 2036
Convertible senior subordinated notes conversion price										$ 40.73		$ 40.73
Convertible senior subordinated notes, conversion rate												24.5525
Convertible senior subordinated notes, principal amount										1,000		1,000
Convertible senior subordinated notes, triggering event, percent of closing sales price to conversion price												120.00%
Days within trading period required to trigger qualifying event									20
Trading period in which qualifying event must occur									30 days
Maximum borrowing capacity on line of credit facility																				600,000,000	385,000,000
Periodic payment required on term loan																					5,000,000	10,000,000
Margin on variable rate			0.50%	1.00%	1.00%	0.00%	2.00%	0.50%
Credit facility	600,000,000	665,000,000
Remaining borrowing capacity on line of credit facility	385,000,000	335,000,000
Long-term debt, estimated fair value										249,600,000		249,600,000		252,400,000				324,600,000	298,900,000
Long-term debt, carrying value										189,900,000		189,900,000		183,400,000	257,100,000		259,400,000	300,000,000	300,000,000
Outstanding letters of credit	$ 16,900,000	$ 15,600,000