Long-Term Obligations (Details) (USD $) In Thousands, unless otherwise specified							9 Months Ended
	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014 Senior term notes [Member]	Dec. 31, 2013 Senior term notes [Member]	Sep. 30, 2014 Secured seller notes [Member]	Dec. 31, 2013 Secured seller notes [Member]	Sep. 30, 2014 Federal funds rate [Member] Senior term notes [Member]	Sep. 30, 2014 Eurodollar [Member] Senior term notes [Member]	Sep. 30, 2014 Tier 1 [Member] New Senior Credit Facility [Member]	Sep. 30, 2014 Tier 1 [Member] Eurodollar [Member] New Senior Credit Facility [Member]	Sep. 30, 2014 Tier 1 [Member] Base Rate [Member] New Senior Credit Facility [Member]	Sep. 30, 2014 Tier 2 [Member] New Senior Credit Facility [Member]	Sep. 30, 2014 Tier 2 [Member] Eurodollar [Member] New Senior Credit Facility [Member]	Sep. 30, 2014 Tier 2 [Member] Base Rate [Member] New Senior Credit Facility [Member]	Sep. 30, 2014 Tier 3 [Member] New Senior Credit Facility [Member]	Sep. 30, 2014 Tier 3 [Member] Eurodollar [Member] New Senior Credit Facility [Member]	Sep. 30, 2014 Tier 3 [Member] Base Rate [Member] New Senior Credit Facility [Member]	Sep. 30, 2014 Tier 4 [Member] New Senior Credit Facility [Member]	Sep. 30, 2014 Tier 4 [Member] Eurodollar [Member] New Senior Credit Facility [Member]	Sep. 30, 2014 Tier 4 [Member] Base Rate [Member] New Senior Credit Facility [Member]	Sep. 30, 2014 Tier 5 [Member] New Senior Credit Facility [Member]	Sep. 30, 2014 Tier 5 [Member] Eurodollar [Member] New Senior Credit Facility [Member]	Sep. 30, 2014 Tier 5 [Member] Base Rate [Member] New Senior Credit Facility [Member]	Sep. 30, 2014 Tier 6 [Member] New Senior Credit Facility [Member]	Sep. 30, 2014 Tier 6 [Member] Eurodollar [Member] New Senior Credit Facility [Member]	Sep. 30, 2014 Tier 6 [Member] Base Rate [Member] New Senior Credit Facility [Member]	Sep. 30, 2014 Minimum [Member] Tier 1 [Member]	Sep. 30, 2014 Minimum [Member] Tier 2 [Member]	Sep. 30, 2014 Minimum [Member] Tier 3 [Member]	Sep. 30, 2014 Minimum [Member] Tier 4 [Member]	Sep. 30, 2014 Minimum [Member] Tier 5 [Member]	Sep. 30, 2014 Maximum [Member] Tier 2 [Member]	Sep. 30, 2014 Maximum [Member] Tier 3 [Member]	Sep. 30, 2014 Maximum [Member] Tier 4 [Member]	Sep. 30, 2014 Maximum [Member] Tier 5 [Member]	Sep. 30, 2014 Maximum [Member] Tier 6 [Member]	Sep. 30, 2014 Revolving line of credit [Member]	Dec. 31, 2013 Revolving line of credit [Member]
Debt Instrument [Line Items]
Debt obligations	$ 600,230	$ 557,144	$ 600,000	$ 556,914	$ 230	$ 230																															$ 0	$ 0
Capital lease obligations	60,180	62,501
Debt and capital lease obligations	660,410	619,645
Less - current portion	(11,687)	(51,087)
Long-term debt and capital lease obligations	648,723	568,558
Effective interest rate			1.91%	1.92%
Stated interest rate					10.00%
Consolidated Leverage Ratio																											4	3.25	2.50	1.75	1.00	4	3.25	2.5	1.75	1.00
Applicable margin for borrowings										2.25%	1.25%		2.00%	1.00%		1.75%	0.75%		1.50%	0.50%		1.25%	0.25%		1.00%	0.00%
Commitment Fee									0.45%			0.40%			0.35%			0.30%			0.25%			0.25%
Long-term Debt and Capital Lease Obligations, Including Current Maturities [Abstract]
2014	0
2015	15,000
2016	30,000
2017	37,500
2018	52,500
Thereafter	$ 465,000
Basis spread on variable interest rate							0.05%	1.00%