Long-Term Debt (Details) (USD $)				6 Months Ended							6 Months Ended		6 Months Ended		6 Months Ended		6 Months Ended				6 Months Ended			6 Months Ended				1 Months Ended	6 Months Ended
	Jun. 30, 2012	Dec. 31, 2011	Jun. 02, 2007 Interest Rate Swap	Jun. 30, 2012 PIK toggle notes	Dec. 31, 2011 PIK toggle notes	Jul. 24, 2012 PIK toggle notes Subsequent event	Jun. 30, 2012 PIK toggle notes Maximum	Jul. 24, 2012 PIK toggle notes Maximum Subsequent event	Jun. 30, 2012 PIK toggle notes Minimum	Jul. 24, 2012 PIK toggle notes Minimum Subsequent event	Jun. 30, 2012 PIK toggle notes 2012	Jun. 30, 2012 Existing Notes	Jun. 30, 2012 Existing Notes Subsequent event	Jun. 30, 2012 Additional Notes	Jun. 30, 2012 Floating Rate Notes	Dec. 31, 2011 Floating Rate Notes	Jun. 30, 2012 Senior secured credit facility item	Dec. 31, 2011 Senior secured credit facility	Jun. 30, 2012 Senior secured credit facility Subsequent event	Jun. 30, 2012 Senior secured credit facility Minimum	Jun. 30, 2012 Senior secured credit facility Prime rate	Jun. 30, 2012 Senior secured credit facility Prime rate Maximum	Jun. 30, 2012 Senior secured credit facility Prime rate Minimum	Jun. 30, 2012 Senior secured credit facility Adjusted LIBOR	Jun. 30, 2012 Senior secured credit facility Adjusted LIBOR Maximum	Jun. 30, 2012 Senior secured credit facility Adjusted LIBOR Minimum	Jul. 31, 2012 Second Amended and Restated Credit Agreement Subsequent event	Aug. 31, 2012 2012 Notes Subsequent event	Jun. 30, 2012 2012 Notes Subsequent event	Aug. 07, 2012 2012 Notes Subsequent event	Jun. 30, 2012 Capital lease obligations	Dec. 31, 2011 Capital lease obligations
Long-Term Debt
Unamortized bond premium	$ 2,985,000	$ 3,433,000
Long-Term Debt current and noncurrent	703,364,000	671,097,000		405,000,000	405,000,000										230,000,000	230,000,000	47,500,000	14,500,000													17,879,000	18,164,000
Less: Current portion of long-term debt	(6,701,000)	(5,627,000)
Total long-term debt	696,663,000	665,470,000
Interest rate (as a percent)							9.25%	9.25%	8.50%	8.50%																				7.625%
Aggregate outstanding principal amount				405,000,000								230,000,000		175,000,000	230,000,000
Redemption price (as a percent)											102.125%				100.00%
Repurchase price, as percentage of principal amount, if Company undergoes change of control				101.00%											101.00%
Base rate															LIBOR						Prime			Adjusted LIBOR
Margin over base rate (as a percent)															3.375%							2.00%	1.75%		3.00%	2.75%
LIBOR-based rate (as a percent)															4.112%
Amount of interest rate swap agreements			230,000,000
Maximum borrowing capacity under the facility before amendment																	135,000,000
Maximum borrowing capacity																	195,000,000		195,000,000								235,000,000
Capitalized deferred financing costs related to the Amended and Restated Credit Agreement																	1,700,000
Availability amount																	142,500,000
Borrowing base																	195,000,000
Letters of credit																	5,000,000
Available borrowing capacity to be maintained																				15,000,000
Minimum ratio of EBITDA to cash expense, number of quarters																	4
Borrowing outstanding																	47,500,000
Extension period prior to the maturity date of the debt instrument													90 days																90 days
Principal amount of debt issued																												425,000,000
Debt repurchased						$ 405,000,000