Accrued Expenses (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Accrued Liabilities, Current [Abstract]
Accrued interest	$ 26,373us-gaap_InterestPayableCurrent	$ 19,408us-gaap_InterestPayableCurrent
Accrued bonus	12,049us-gaap_AccruedBonusesCurrent	11,108us-gaap_AccruedBonusesCurrent
Accrued insurance	50,470us-gaap_AccruedInsuranceCurrent	49,170us-gaap_AccruedInsuranceCurrent
Accrued property and other taxes	15,980	11,788
Construction retainage	3,412us-gaap_ConstructionPayableCurrent	267us-gaap_ConstructionPayableCurrent
Other	32,328us-gaap_OtherAccruedLiabilitiesCurrent	23,209us-gaap_OtherAccruedLiabilitiesCurrent
Total	$ 140,612us-gaap_AccruedLiabilitiesCurrent	$ 114,950us-gaap_AccruedLiabilitiesCurrent

Carrying value as of the balance sheet date of obligations incurred and payable for real and property taxes. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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Carrying value as of the balance sheet date of obligations incurred and payable for incentive compensation awarded to employees and directors or earned by them based on the terms of one or more relevant arrangements. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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- Definition

Carrying value as of the balance sheet date of obligations incurred through that date and payable to insurance entities to mitigate potential loss from various risks or to satisfy a promise to provide certain coverage's to employees. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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- Definition

Carrying value as of the balance sheet date of [accrued] interest payable on all forms of debt, including trade payables, that has been incurred and is unpaid. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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- Definition

Carrying value as of the balance sheet date of obligations incurred through that date and payable arising from transactions not otherwise specified in the taxonomy. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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