Income Taxes (Details 4) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Deferred tax assets:
Net operating loss carryforwards	$ 142,401	$ 169,533
Inventory	6,525us-gaap_DeferredTaxAssetsInventory	6,684us-gaap_DeferredTaxAssetsInventory
Alternative minimum tax credit carryforwards	5,685	5,615
Accrued liabilities	16,260	14,446
Foreign tax credit carryforwards	136,864	124,850
Other	38,901us-gaap_DeferredTaxAssetsOther	40,608us-gaap_DeferredTaxAssetsOther
Subtotal	346,636us-gaap_DeferredTaxAssetsGross	361,736us-gaap_DeferredTaxAssetsGross
Valuation allowances	(112,995)	(102,418)
Total deferred tax assets	233,641us-gaap_DeferredTaxAssetsNet	259,318us-gaap_DeferredTaxAssetsNet
Deferred tax liabilities:
Property, plant and equipment	(181,887)	(209,297)
Basis difference in the Partnership	(136,438)	(104,079)
Total deferred tax liabilities	(318,325)us-gaap_DeferredTaxLiabilities	(313,376)us-gaap_DeferredTaxLiabilities
Net deferred tax liabilities	$ (84,684)us-gaap_DeferredTaxAssetsLiabilitiesNet	$ (54,058)us-gaap_DeferredTaxAssetsLiabilitiesNet

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