Components of Purchase Price Allocation (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Nov. 14, 2014	Mar. 31, 2014
Business Combinations [Abstract]
Cash and cash equivalents		$ 219
Accounts Receivable		14,640
Inventories		9,627
Prepaid and Other Assets		753
Property and Equipment		192,738
Intangible Assets	56,200	56,200
Indemnity under Sales Agreement		14,810
Other Assets		1,120
Accounts Payable		(4,343)
Accrued Liabilities		(2,585)
Obligations under Long-term Sales Agreements		(28,131)
Asset Retirement Obligation		(4,112)
Deferred Taxes		(13,765)
Total Net Assets		237,171
Goodwill	132,515us-gaap_Goodwill		132,515us-gaap_Goodwill
Total Estimated Purchase Price		$ 237,171

Business combination recognized identifiable assets acquired and liabilities assumed accrued liabilities.

No definition available.

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- Definition

Business combination recognized identifiable assets acquired and liabilities assumed asset retirement obligations.

+ References

No definition available.

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- Definition

Indemnification of purchaser of certain liabilities obtained in the business combination.

+ References

No definition available.

+ Details

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- Definition

Amount of currency on hand as well as demand deposits with banks or financial institutions, acquired at the acquisition date. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

+ References

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- Definition

Amount of other assets expected to be realized or consumed before one year or the normal operating cycle, if longer, acquired at the acquisition date.

+ References

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- Definition

Amount of asset related to consideration paid in advance for costs that provide economic benefits in future periods, and amount of other assets that are expected to be realized or consumed within one year or the normal operating cycle, if longer, acquired at the acquisition date.

+ References

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- Definition

Amount due from customers or clients for goods or services, including trade receivables, that have been delivered or sold in the normal course of business, and amounts due from others, including related parties expected to be converted to cash, sold or exchanged within one year or the normal operating cycle, if longer, acquired at the acquisition date.

+ References

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- Definition

Amount of liabilities incurred for goods and services received that are used in an entity's business and related party payables, assumed at the acquisition date.

+ References

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- Definition

Amount of deferred tax liability attributable to taxable temporary differences due after one year or the normal operating cycle, if longer, assumed at the acquisition date.

+ References

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- Definition

Amount of intangible assets, excluding goodwill, acquired at the acquisition date.

+ References

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- Definition

The amount of inventory recognized as of the acquisition date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (c)

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-Topic 805

-SubTopic 10

-Section 55

-Paragraph 37

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- Definition

Amount recognized as of the acquisition date for the identifiable assets acquired in excess of (less than) the aggregate liabilities assumed.

+ References

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- Definition

Amount of other liabilities due after one year or the normal operating cycle, if longer, assumed at the acquisition date.

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- Definition

The amount of property, plant, and equipment recognized as of the acquisition date.

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- Definition

Amount recognized for assets, including goodwill, in excess of (less than) the aggregate liabilities assumed.

+ References

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- Definition

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

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-Topic 350

-SubTopic 20

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

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