Long-Term Debt and Capital Lease Obligations (Long-Term Debt) (Details) (USD $) In Thousands, unless otherwise specified											3 Months Ended	12 Months Ended
	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2012 2.25% Senior convertible debentures	Mar. 31, 2012 2.25% Senior convertible debentures	Dec. 31, 2011 2.25% Senior convertible debentures	Mar. 26, 2011 2.25% Senior convertible debentures	Jun. 30, 2012 Term loan facilities	Dec. 31, 2011 Term loan facilities	Jun. 30, 2012 Revolving credit facility	Dec. 31, 2011 Revolving credit facility	Mar. 31, 2012 Other long-term debt represents secured and unsecured promissory notes, interest rates ranging from 0% to 0.5%, 0% to 0.5% at both March 31, 2012 and December 31, 2011, respectively, maturing between 2012 and 2013	Dec. 31, 2011 Other long-term debt represents secured and unsecured promissory notes, interest rates ranging from 0% to 0.5%, 0% to 0.5% at both March 31, 2012 and December 31, 2011, respectively, maturing between 2012 and 2013	Jun. 30, 2012 Other long-term debt represents secured and unsecured promissory notes, interest rates ranging from 0% to 0.5%, 0% to 0.5% at both March 31, 2012 and December 31, 2011, respectively, maturing between 2012 and 2013
Debt Instrument
Principal	$ 700,637		$ 349,995		$ 349,995
Unamortized debt discount			(14,433)		(21,533)
Total debt	686,204	717,902	335,562		328,462		315,420	356,322	35,000	33,000		118	222
Less: current portion of long-term debt	(134,812)	(14,732)	100,670
Long-term debt	$ 551,392	$ 703,170
Interest rate on debt (as a percent)			2.25%	2.25%	2.25%	2.25%
Interest rate on debt, minimum (as a percent)											0.00%	0.00%
Interest rate on debt, maximum (as a percent)											0.50%	0.50%