Income Taxes - Deferred Tax Assets and Liabilities (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Deferred tax assets:
Deferred compensation	$ 50,829	$ 48,401
Deferred income	16,305us-gaap_DeferredTaxAssetsDeferredIncome	30,101us-gaap_DeferredTaxAssetsDeferredIncome
Accrued expenses	9,235	8,441
Other	27,808us-gaap_DeferredTaxAssetsOther	11,921us-gaap_DeferredTaxAssetsOther
Gross deferred tax assets	104,177us-gaap_DeferredTaxAssetsGross	98,864us-gaap_DeferredTaxAssetsGross
Valuation allowance	0	0
Total deferred tax assets	104,177us-gaap_DeferredTaxAssetsNet	98,864us-gaap_DeferredTaxAssetsNet
Deferred tax liabilities:
Property and equipment	128,958	129,441
Unremitted foreign earnings	238,133	157,091
Basis difference in equity investments	(8,947)	10,843
Other	1,088us-gaap_DeferredTaxLiabilitiesOther	707us-gaap_DeferredTaxLiabilitiesOther
Total deferred tax liabilities	272,949us-gaap_DeferredTaxLiabilities	199,218us-gaap_DeferredTaxLiabilities
Deferred Tax Liabilities, Gross	377,126us-gaap_DeferredIncomeTaxLiabilities	298,082us-gaap_DeferredIncomeTaxLiabilities
Net deferred income tax liability	272,949us-gaap_DeferredTaxAssetsLiabilitiesNet	199,218us-gaap_DeferredTaxAssetsLiabilitiesNet
Deferred Tax Assets (Liabilities), Net [Abstract]
Deferred tax liabilities	322,758	260,807
Deferred income taxes	(49,809)us-gaap_DeferredTaxAssetsNetCurrent	(61,589)us-gaap_DeferredTaxAssetsNetCurrent
Net deferred income tax liability	$ 272,949us-gaap_DeferredTaxAssetsLiabilitiesNet	$ 199,218us-gaap_DeferredTaxAssetsLiabilitiesNet

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