Long-Term Indebtedness (Details 2) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012
Summary of Long-term debt
Net discount	$ (7,801)	$ (8,109)
Long-term debt	1,403,941	1,405,206
Less current portion	(6,247)	(6,240)
Total long-term debt	1,397,694	1,398,966
Term Loan B
Summary of Long-term debt
Long-term debt	580,732	582,187	470,000
Senior unsecured 2021 Notes
Summary of Long-term debt
Long-term debt	800,000	800,000
HWP Refinance Loan
Summary of Long-term debt
Long-term debt	$ 31,010	$ 31,128