Long-Term Debt (Details) (USD $)	12 Months Ended				12 Months Ended							1 Months Ended	12 Months Ended			12 Months Ended		0 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 05, 2012	Dec. 31, 2012 Senior Notes	Dec. 31, 2011 Senior Notes	Nov. 25, 2009 Senior Notes	Dec. 31, 2012 2017 notes	Dec. 31, 2011 2017 notes	Dec. 31, 2012 2019 notes	Dec. 31, 2011 2019 notes	Jun. 30, 2011 Senior Secured Revolving Credit Facility	Dec. 31, 2012 Senior Secured Revolving Credit Facility	Dec. 31, 2011 Senior Secured Revolving Credit Facility	Jun. 03, 2011 Senior Secured Revolving Credit Facility	Dec. 31, 2012 Senior Secured Revolving Credit Facility Equal to or less than	Dec. 31, 2012 Senior Secured Revolving Credit Facility Equal to or greater than	Nov. 25, 2009 Prior secured revolving credit facility	Dec. 31, 2012 Letters of credit	Dec. 31, 2012 Letters of credit Equal to or less than	Dec. 31, 2012 Letters of credit Equal to or greater than
Debt
Principal	$ 600,000,000	$ 600,000,000						$ 300,000,000	$ 300,000,000	$ 300,000,000	$ 300,000,000
Carrying Value	596,506,000	596,077,000						298,471,000	298,237,000	298,035,000	297,841,000
Fair Value	662,118,000	655,500,000						329,418,000	327,750,000	332,700,000	327,750,000
Interest expense, net of amounts capitalized
Interest expense	36,327,000	33,866,000	46,938,000
Interest rate (as a percent)								8.25%		8.50%										2.50%	1.75%
Unamortized debt issuance costs					10,325,000	11,613,000	14,200,000						7,684,000	9,927,000
Lender fees and costs																		15,900,000
Ownership interest in Decker (as a percent)	50.00%			50.00%	50.00%
Percentage of principal amount at which notes may be required to be repurchased in event of change of control					101.00%
Maximum amount under senior secured revolving credit facility															500,000,000			400,000,000
Additional borrowing capacity available on the credit facility												200,000,000
Charge to write off deferred financing costs												1,000,000
New deferred financing costs															2,200,000
Term of revolving credit facility													5 years
Base rate on line of credit facility interest rate													LIBOR
Margin over base rate on line of credit facility interest rate (as a percent)																2.50%	1.75%
Commitment fee payable to lender (as a percent)																0.50%	0.25%
Interest rate at the end of the period (as a percent)																			2.50%
Fronting fee payable in connection with the issuance of a letter of credit (as a percent)													0.25%
Ratio of EBITDA to consolidated cash interest expense through June, 2013																3.75	2.50
Ratio of EBITDA to consolidated cash interest expense after June 2013																3.50	2.75
Aggregate future maturities of long-term debt
2017	300,000,000
2018 and thereafter	300,000,000
Less discount on senior notes	(3,494,000)							(1,979,000)		(2,337,000)
Total long term debt	$ 596,506,000	$ 596,077,000						$ 298,471,000	$ 298,237,000	$ 298,035,000	$ 297,841,000