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Equity Investment - Additional Information (Detail) - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2015 | Dec. 31, 2014 | Dec. 31, 2013
Schedule of Equity Method Investments [Line Items] |  |  |
Distributions from equity method Investment | $ 46,795 | $ 43,005 | $ 24,113
Weighted average useful life of assets (in years) | 28 years |  |
Ciner Wyoming |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Percentage of partnership interest owned (percent) | 49.00% |  |
Ciner Wyoming |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Percentage of partnership interest owned (percent) | 49.00% |  |
Distributions from equity method Investment | $ 46,800 | 46,600 | $ 72,900
Increase in fair value of property, plant and equipment | $ 154,800 | $ 162,700 |

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- Definition Difference between amount at which an investment accounted for under the equity method of accounting is carried (reported) on the balance sheet and amount of underlying equity in net assets the reporting Entity has in the investee. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33918-111571 + Details
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- Definition The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33918-111571 + Details
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