Debt (Details) (USD $)	1 Months Ended	3 Months Ended	12 Months Ended				0 Months Ended			0 Months Ended	12 Months Ended		12 Months Ended			0 Months Ended										12 Months Ended	0 Months Ended		12 Months Ended
	Dec. 31, 2010	Jun. 30, 2012	Dec. 31, 2012	Sep. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Dec. 22, 2010 10.75% senior notes due 2019	Dec. 31, 2012 10.75% senior notes due 2019	Dec. 31, 2011 10.75% senior notes due 2019	Dec. 22, 2010 Senior secured Term Loan B due 2016, net of discount	Dec. 31, 2012 Senior secured Term Loan B due 2016, net of discount	Dec. 31, 2011 Senior secured Term Loan B due 2016, net of discount	Dec. 31, 2012 Senior secured Term Loan B due 2016, net of discount Minimum	Apr. 05, 2012 Credit Agreement	Dec. 31, 2012 Credit Agreement Maximum	Apr. 05, 2012 Senior secored Term Loan A due 2017	Dec. 31, 2012 Senior secored Term Loan A due 2017	Dec. 31, 2012 Senior secored Term Loan A due 2017 Minimum	Dec. 31, 2012 Senior secored Term Loan A due 2017 Maximum	Apr. 05, 2012 Senior secured credit facility	Dec. 22, 2010 Senior secured credit facility	Dec. 31, 2012 Obligations under capital leases	Dec. 31, 2011 Obligations under capital leases	Dec. 31, 2012 Notes payable and other	Dec. 31, 2011 Notes payable and other	Dec. 31, 2012 Extended revolving credit facility	Dec. 22, 2010 7.75% senior notes	Oct. 03, 2005 7.75% senior notes	Dec. 31, 2012 Standby letters of credit
Long-term debt and obligations under capital leases
Long-term debt and capital lease obligation			$ 390,799,000			$ 369,825,000		$ 200,000,000	$ 200,000,000			$ 165,487,000					$ 170,625,000					$ 17,683,000	$ 431,000	$ 2,491,000	$ 3,907,000
Less current portion		5,810,000	20,747,000	5,930,000	5,694,000	4,629,000																6,000,000
Long-term debt and obligations under capital leases			370,052,000			365,196,000
Interest rate (as a percent)							10.75%	10.75%	10.75%																		7.75%
Discount												2,800,000
Issuance of debt							200,000,000			170,000,000																		150,000,000
Debt instrument issuance as a percentage of the face amount							100.00%			98.00%																		99.261%
Debt repurchased																											120,000,000
Debt satisfied and discharged by delivering redemption amount																											30,000,000
Aggregate amount available														375,000,000		175,000,000				200,000,000	275,000,000					240,000,000
Option to increase the available additional borrowing capacity										175,000,000					175,000,000											175,000,000
Net proceeds from issuance of debt	366,600,000		175,000,000							166,600,000
Repayment of preferred equity plus accrued dividends										159,600,000
Annual amortization percentage											1.00%
Variable rate basis											LIBOR															LIBOR
Interest rate margin (as a percent)											5.50%						2.75%	2.25%	3.00%							2.75%
Reference rate (as a percent)													1.75%
Percentage of original principal amount to be amortized during each of the first two years after funding																5.00%
Number of years after funding during which five percent of original principal amount will be amortized																2 years
Percentage of original principal amount to be amortized during the third year after funding																10.00%
Percentage of original principal amount to be amortized during the final two years of the term																15.00%
Number of final years of the term of loan during which 15 percent of original principal amount will be amortized																2 years
Loss on extinguishment of debt		7,100,000	7,129,000
Amount outstanding																													59,000,000
Available capacity																										141,000,000
Interest rate at period end (as a percent)																													2.88%
Commitment fee on the unused balance (as a percent)																													0.50%
Maturities of long-term debt and obligations under capital leases
2013			20,747,000
2014			16,704,000
2015			24,885,000
2016			29,247,000
2017			99,216,000
Thereafter			200,000,000
Long-term debt and obligations			$ 390,799,000																								$ 30,000,000