Long-Term Obligations (Details 1) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Maturities of Long-term Debt [Abstract]
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	$ 51,089
Long-term Debt, Maturities, Repayments of Principal in Year Two	54,708
Long-term Debt, Maturities, Repayments of Principal in Year Three	461,452
Long-term Debt, Maturities, Repayments of Principal in Year Four	3,490
Long-term Debt, Maturities, Repayments of Principal in Year Five	3,805
Long-term Debt, Maturities, Repayments of Principal after Year Five	45,101
Long-term Debt	557,144	592,688
Capital Lease Obligations	62,501	37,955
Debt Instrument, Basis Spread on Variable Rate	1.75%
Leverage Ratio	1.81
Debt and Capital Lease Obligations	619,645	630,643
Senior Notes [Member]
Maturities of Long-term Debt [Abstract]
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	47,574
Long-term Debt, Maturities, Repayments of Principal in Year Two	51,289
Long-term Debt, Maturities, Repayments of Principal in Year Three	458,281
Long-term Debt, Maturities, Repayments of Principal in Year Four	0
Long-term Debt, Maturities, Repayments of Principal in Year Five	0
Long-term Debt, Maturities, Repayments of Principal after Year Five	0
Capital Lease Obligations [Member]
Maturities of Long-term Debt [Abstract]
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	3,515
Long-term Debt, Maturities, Repayments of Principal in Year Two	3,419
Long-term Debt, Maturities, Repayments of Principal in Year Three	3,171
Long-term Debt, Maturities, Repayments of Principal in Year Four	3,490
Long-term Debt, Maturities, Repayments of Principal in Year Five	3,805
Long-term Debt, Maturities, Repayments of Principal after Year Five	$ 45,101
Leverage Ratio Level One [Member]
Maturities of Long-term Debt [Abstract]
Debt Instrument, Basis Spread on Variable Rate	2.25%
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage	0.50%
Leverage Ratio	≥ 2.50:1.00
Leverage Ratio Level Two [Member]
Maturities of Long-term Debt [Abstract]
Debt Instrument, Basis Spread on Variable Rate	1.75%
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage	0.375%
Leverage Ratio	< 2.50:1.00 and ≥ 1.75:1.00
Leverage Ratio Level Three [Member]
Maturities of Long-term Debt [Abstract]
Debt Instrument, Basis Spread on Variable Rate	1.50%
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage	0.25%
Leverage Ratio	< 1.75:1.00 and ≥ 1.00:1.00
Leverage Ratio Level Four [Member]
Maturities of Long-term Debt [Abstract]
Debt Instrument, Basis Spread on Variable Rate	1.25%
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage	0.20%
Leverage Ratio	< 1.00:1.00