Miller Energy Resources (MILL) 10-Q 12 Mar 15 2015 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Jan. 31, 2015	Feb. 26, 2015
DOCUMENT AND ENTITY INFORMATION
Entity Registrant Name	MILLER ENERGY RESOURCES, INC.
Entity Central Index Key	785968
Current Fiscal Year End Date	-26
Entity Filer Category	Accelerated Filer
Document Type	10-Q
Document Period End Date	31-Jan-15
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q3
Amendment Flag	FALSE
Entity Common Stock, Shares Outstanding		46,664,223

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Jan. 31, 2015	Apr. 30, 2014
In Thousands, unless otherwise specified
CURRENT ASSETS:
Cash and cash equivalents	$2,239	$5,749
Restricted cash	147	679
Accounts receivable, net of allowances of $50 and $252	14,064	6,409
Alaska production credits receivable, net of allowances of $2,390 and $7,124	63,328	49,121
Inventory	3,697	5,102
Prepaid expenses and other	4,522	3,852
Short-term portion of derivative instruments	29,513	88
Assets held for sale	2,471	236
Total current assets	119,981	71,236
OIL AND GAS PROPERTIES, NET	189,722	644,827
EQUIPMENT, NET	51,691	35,369
OTHER ASSETS:
Land	15	1,848
Restricted cash, non-current	15,092	12,075
Deferred financing costs, net	3,364	803
Long-term portion of derivative instruments	12,027	26
Other assets	667	638
Total assets	392,559	766,822
CURRENT LIABILITIES:
Accounts payable	59,380	38,836
Accrued expenses	11,641	20,446
Short-term portion of derivative instruments		3,315
Deferred income taxes	7,620	2,858
Current portion of long-term debt and capital leases	29,553	9,459
Liabilities associated with assets held for sale	950
Total current liabilities	109,144	74,914
OTHER LIABILITIES:
Deferred income taxes	6,895	139,768
Asset retirement obligation	24,588	22,872
Long-term portion of derivative instruments		4,006
Long-term debt and capital leases, less current portion	196,252	174,743
Other	31
Total liabilities	336,910	416,303
MEZZANINE EQUITY:
Series C Cumulative Preferred Stock, redemption amount of $82,730 and $78,124, 3,250,000 shares authorized, 3,250,000 and 3,069,968 shares issued and outstanding as of January 31, 2015 and April 30, 2014, respectively	71,738	67,760
STOCKHOLDERS' EQUITY:
Series D Cumulative Redeemable Preferred Stock, redemption amount of $83,984 and $32,378, 4,000,000 shares authorized, 3,330,608 and 1,070,448 shares issued and outstanding as of January 31, 2015 and April 30, 2014, respectively	60,090	30,041
Series D Cumulative Redeemable Preferred Stock, 0 and 213,586 shares held in escrow as of January 31, 2015 and April 30, 2014, respectively		5,000
Common stock, $0.0001 par, 500,000,000 shares authorized, 46,662,223 and 45,756,697 shares issued and outstanding as of January 31, 2015 and April 30, 2014, respectively	5	4
Additional paid-in capital	110,693	98,788
Retained earnings (accumulated deficit)	-186,877	158,926
Total stockholders' equity (deficit)	-16,089	282,759
Total liabilities and stockholders' equity	$392,559	$766,822

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Jan. 31, 2015	Apr. 30, 2014
In Thousands, except Share data, unless otherwise specified
Allowance for accounts receivable	$50	$252
Allowances for Alaska production credits receivable	2,390	7,124
Common Stock
Par value (in dollars per share)	$0.00	$0.00
Shares authorized (in shares)	500,000,000	500,000,000
Shares issued (in shares)	46,662,223	45,756,697
Shares outstanding (in shares)	46,662,223	45,756,697
Series C Preferred Stock [Member]
Preferred Stock
Series C redemption amount	82,730	78,124
Shares authorized (in shares)	3,250,000	3,250,000
Shares issued (in shares)	3,250,000	3,069,968
Shares outstanding (in shares)	3,250,000	3,069,968
Series D Preferred Stock [Member]
Preferred Stock
Series D redemption amount	$83,984	$32,378
Shares authorized (in shares)	4,000,000	4,000,000
Shares issued (in shares)	3,330,608	1,070,448
Shares outstanding (in shares)	3,330,608	1,070,448
Shares held In escrow (in shares)		213,586

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Operations (Unaudited) (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Share data, unless otherwise specified	Jan. 31, 2015	Jan. 31, 2014	Jan. 31, 2015	Jan. 31, 2014
REVENUES:
Oil sales	$14,953	$16,348	$52,298	$47,012
Natural gas sales	4,768	118	16,430	671
Other	550	162	1,098	749
Total revenues	20,271	16,628	69,826	48,432
OPERATING EXPENSES:
Lease operating expense	8,803	4,410	24,392	15,226
Transportation costs	1,607	1,411	4,149	3,023
Cost of purchased gas sold	316		2,572
Cost of other revenue	640	256	1,305	844
General and administrative	7,358	7,587	34,770	21,092
Alaska carried-forward annual loss credits, net	-21,508		-24,240
Exploration expense	77,740	352	244,848	786
Depreciation, depletion and amortization	19,541	7,642	56,601	22,352
Accretion of asset retirement obligation	370	305	1,067	903
Impairment of proved properties and other long-lived assets	117,037		230,771	0
Other operating expense, net	900	1,250	904	1,250
Total operating expense	212,804	23,213	577,139	65,476
OPERATING LOSS	-192,533	-6,585	-507,313	-17,044
OTHER INCOME (EXPENSE):
Interest expense, net	-2,478	-407	-8,896	-4,051
Gain (loss) on derivatives, net	39,330	1,677	55,516	-5,589
Other income, net	404	42	559	26
Total other income (expense)	37,256	1,312	47,179	-9,614
LOSS BEFORE INCOME TAXES	-155,277	-5,273	-460,134	-26,658
Income tax benefit	3,016	2,171	128,111	11,640
NET LOSS	-152,261	-3,102	-332,023	-15,018
Accretion of Series C and D preferred stock	-1,271	-817	-3,005	-1,935
Series C and D preferred stock cumulative dividends	-4,369	-2,905	-10,775	-7,573
NET LOSS ATTRIBUTABLE TO COMMON STOCKHOLDERS	($157,901)	($6,824)	($345,803)	($24,526)
LOSS PER COMMON SHARE:
Basic (in dollars per share)	($3.39)	($0.15)	($7.47)	($0.56)
Diluted (in dollars per share)	($3.39)	($0.15)	($7.47)	($0.56)
WEIGHTED AVERAGE NUMBER OF COMMON SHARES:
Basic (in shares)	46,644,887	44,886,838	46,311,958	44,141,222
Diluted (in shares)	46,644,887	44,886,838	46,311,958	44,141,222

Condensed_Consolidated_Stateme1

Condensed Consolidated Statement of Stockholders' Equity (USD $)	Total	Series C Preferred Stock [Member]	Series D Preferred Stock [Member]	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings (Accumulated Deficit) [Member]	Retained Earnings (Accumulated Deficit) [Member]	Retained Earnings (Accumulated Deficit) [Member]
In Thousands, except Share data, unless otherwise specified				Series D Preferred Stock [Member]				Series C Preferred Stock [Member]	Series D Preferred Stock [Member]
Balance at April 30, 2014 at Apr. 30, 2014	$282,759			$25,041	$4	$98,788	$158,926
Balance at April 30, 2014 (in shares) at Apr. 30, 2014				1,070,448	45,756,697
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	-332,023						-332,023
Preferred stock dividends		-6,309	-4,466					-6,309	-4,466
Accretion of preferred stock		-2,179		826				-2,179	-826
Issuance of Series D preferred stock			34,223	34,223
Issuance of Series D preferred stock (in shares)				2,260,160
Issuance of equity for services	615					615
Issuance of equity for compensation	9,881					9,881
Issuance of equity for compensation (in shares)					575,587
Exercise of equity rights	1,410				1	1,409
Exercise of equity rights (in shares)	329,939				329,939
Balance at January 31, 2015 at Jan. 31, 2015	($16,089)			$60,090	$5	$110,693	($186,877)
Balance at January 31, 2015 (in shares) at Jan. 31, 2015				3,330,608	46,662,223

Condensed_Consolidated_Stateme2

Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2015	Jan. 31, 2014
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	($332,023)	($15,018)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation, depletion and amortization	56,601	22,352
Amortization of deferred financing fees and debt discount	1,288	1,113
Expense from issuance of equity	10,857	5,120
Non-cash exploration expenses	242,980	157
Impairment of proved properties and other long-lived assets	230,771	0
Deferred income taxes	-128,111	-11,640
Derivative contracts:
(Gain) loss on derivatives, net	-55,516	5,589
Cash settlements received (paid)	6,769	-2,765
Alaska carried-forward annual loss credits, net	-24,240
Accretion of asset retirement obligation	1,067	903
Other, net	2,350	1,949
Changes in operating assets and liabilities (excluding effects of acquisitions):
Receivables	14,694	5,084
Inventory	-232	372
Prepaid expenses and other assets	-876	-1,788
Accounts payable, accrued expenses and other	593	3,849
NET CASH PROVIDED BY OPERATING ACTIVITIES	26,972	15,277
CASH FLOWS FROM INVESTING ACTIVITIES:
Capital expenditures for oil and gas properties	-110,953	-94,388
Purchase of equipment and improvements	-16,318	-986
Proceeds from Alaska expenditure and exploration based credits	36,809	18,561
Prepayment of drilling costs		-2,302
Cash paid for Savant acquisition, net of cash acquired	-1,448	0
Proceeds from sale of assets	4,191	0
Deposits for potential acquisition		-3,000
NET CASH USED IN INVESTING ACTIVITIES	-87,719	-82,115
CASH FLOWS FROM FINANCING ACTIVITIES:
Cash dividends	-9,312	-5,646
Payments on debt	-16,917	0
Proceeds from borrowings	54,000	20,000
Proceeds from capital lease obligations	3,250
Principal payments on capital lease obligations	-494
Debt acquisition costs	-3,191	-1,900
Issuance of preferred stock	32,357	62,704
Equity issuance costs	-1,781	-3,893
Exercise of equity rights	1,410	4,538
Restricted cash	-2,085	1,665
Other		3
NET CASH PROVIDED BY FINANCING ACTIVITIES	57,237	77,471
NET CHANGE IN CASH AND CASH EQUIVALENTS	-3,510	10,633
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	5,749	2,551
CASH AND CASH EQUIVALENTS AT END OF PERIOD	2,239	13,184
SUPPLEMENTARY CASH FLOW DATA:
Cash paid for interest	18,492	5,805
SIGNIFICANT NON-CASH INVESTING AND FINANCING ACTIVITIES:
Increase in capital expenditures included in accounts payable and accrued expenses	5,217	32,572
Reduction of oil and gas properties and equipment from applications for Alaska expenditure and exploration based credits	45,979	28,906
Accretion of preferred stock	3,005	1,935
Issuance of Series D Preferred Stock held in escrow	0	5,000
Issuance of Series D Preferred Stock for Anchor Point Pipeline	5,446	0
Promissory note for Savant acquisition	$2,000	$0

Organization_and_Basis_of_Pres

Organization and Basis of Presentation	9 Months Ended
	Jan. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Basis of Presentation	ORGANIZATION AND BASIS OF PRESENTATION
	Overview
	Unless specifically set forth to the contrary, when used in this report, the terms "Miller Energy Resources," the "Company," "we," "us," "ours," "MER," "Miller," and similar terms refer to our Tennessee corporation Miller Energy Resources, Inc., formerly known as Miller Petroleum, Inc., and our subsidiaries, Miller Rig & Equipment, LLC, Savant Alaska, LLC, Nutaaq Operating, LLC, Nutaaq Pipeline, LLC, Miller Drilling, TN LLC, Miller Energy Services, LLC, East Tennessee Consultants, Inc. ("ETC"), East Tennessee Consultants II, LLC ("ETCII"), Miller Energy GP, LLC, Cook Inlet Energy, LLC ("CIE"), and Anchor Point Energy, LLC ("Anchor Point Pipeline") collectively.
	Miller Energy Resources is an independent exploration and production company that utilizes seismic data and other technologies for the geophysical exploration, development and production of oil and natural gas wells in southcentral Alaska, including the Cook Inlet and Kenai Peninsula, as well as Alaska's North Slope. The accounting policies used by the Company and its subsidiaries reflect industry practices and conform to U.S. generally accepted accounting principles ("GAAP").
	Basis of Presentation
	The accompanying condensed consolidated financial statements are presented in accordance with GAAP and, in the opinion of management, include all adjustments (consisting only of normal recurring adjustments) necessary for a fair statement of the results for the interim periods. Certain information and note disclosures normally included in annual financial statements prepared in accordance with GAAP have been condensed or omitted under Securities and Exchange Commission ("SEC") rules and regulations. The results reported in these condensed consolidated financial statements are not necessarily indicative of the financial position or operating results that may be expected for the entire year.
	The financial information included herein should be read in conjunction with the audited consolidated financial statements and notes thereto included in Item 8 of Part II of the Company's Annual Report on Form 10-K for the year ended April 30, 2014, which was filed with the SEC on July 14, 2014, and amended on July 15, 2014.
	Certain amounts in prior fiscal years have been reclassified to conform with the presentation adopted in the current year.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	9 Months Ended
	Jan. 31, 2015
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
	The Company's significant accounting policies are consistent with those disclosed in Miller's Annual Report on Form 10-K for the year ended April 30, 2014.
	Principles of Consolidation
	The accompanying condensed consolidated financial statements include the Company's consolidated accounts after elimination of intercompany balances and transactions. The condensed consolidated financial statements also include the accounts of all investments in which Miller, either through direct or indirect ownership, has more than a 50% interest or significant influence over the management of those entities.
	Use of Estimates
	The preparation of financial statements requires us to utilize estimates and make judgments that affect the reported amounts of assets, liabilities, revenues and expenses and related disclosure of contingent assets and liabilities. These estimates are based on historical experience and on various other assumptions that we believe to be reasonable under the circumstances. The estimates are evaluated by management on an ongoing basis and the results of these evaluations form a basis for making decisions about the carrying value of assets and liabilities that are not readily apparent from other sources. Although actual results may differ from these estimates under different assumptions or conditions, we believe that the estimates used in the preparation of our financial statements are reasonable.
	Oil and Gas Properties
	The Company follows the successful efforts method of accounting for oil and gas properties. Under this method, exploration costs, such as exploratory geological and geophysical costs, delay rentals and exploration overhead, are charged against earnings as incurred. Acquisition costs and costs of drilling exploratory wells are capitalized pending determination of whether proved reserves can be attributed to the area as a result of drilling the well. If management determines that commercial quantities of hydrocarbons have not been discovered, capitalized costs associated with exploratory wells are charged to exploration expense.
	Costs of drilling and equipping successful wells, costs to construct or acquire facilities, and associated asset retirement costs are depleted using the unit-of-production method based on total estimated proved developed reserves. Costs of acquiring proved properties, including leasehold acquisition costs transferred from unproved properties and costs to construct or acquire offshore platforms, and associated asset retirement costs are depleted using the unit-of-production method based on total estimated proved reserves.
	When circumstances indicate that proved properties may be impaired, the Company compares expected undiscounted future net cash flows, calculated using the Company's estimate of future oil and natural gas prices, operating expenses and production, to the net book value of the proved properties on a field by field basis. If the sum of the expected undiscounted future net cash flows is less than the net book value of the proved properties, an impairment loss is recognized for the excess, if any, of the net book value over its estimated fair value. See Note 6 for a discussion of asset impairments.
	Acquisition costs of unproved properties are assessed for impairment during the holding period and transferred to proved oil and gas properties to the extent the costs are associated with successful exploration activities. Significant undeveloped leases are assessed individually for impairment based on our current exploration plans, and a valuation allowance is provided if impairment is indicated. Costs of expired or abandoned leases are charged to expense, while costs of productive leases are transferred to proved oil and gas properties. Costs of maintaining and retaining unproved properties are included in oil and gas operating expense and impairments of unsuccessful leases are included in exploration expense.
	Loss Per Share
	The Company determines basic income (loss) per share and diluted income (loss) per share in accordance with the provisions of ASC 260, "Earnings Per Share." Basic income (loss) per share excludes dilution and is computed by dividing earnings available to common stockholders by the weighted-average number of common shares outstanding for the period. The calculation of diluted earnings (loss) per share is similar to that of basic earnings per share, except that the denominator is increased, if net income is positive, to include the number of additional common shares that would have been outstanding if all potentially dilutive common shares, such as those issuable upon the exercise of stock options and warrants, had been exercised. The Company computes the numerator for basic income (loss) by subtracting accretion of preferred stock and cumulative preferred stock dividends from net income (loss) to arrive at net income (loss) attributable to common stockholders. Preferred stock dividends include dividends declared on preferred stock (regardless of whether the dividends have been paid) and dividends accumulated for the period on cumulative preferred stock (regardless of whether the dividends have been declared). As of January 31, 2015, our cumulative preferred dividends were $10,775.
	Deferred Escalating Minimum Rent
	Certain of Miller's operating leases contain predetermined fixed escalations of the minimum rentals during the term of the lease, which includes option periods where failure to exercise such options would result in an economic penalty. For these leases, the Company recognizes the related rental expense on a straight-line basis over the life of the lease, beginning with the point at which Miller obtains control and possession of the leased properties, and records the difference between the amounts charged to operations and amounts paid as deferred escalating minimum rent. Any lease incentives received are deferred and subsequently amortized on a straight-line basis over the life of the lease as a reduction to rent expense.
	New Accounting Pronouncements Issued But Not Yet Adopted
	In May 2014, the FASB issued ASU 2014-09, "Revenue from Contracts with Customers (Topic 606)." ASU 2014-09 is intended to improve the financial reporting requirements for revenue from contracts with customers by providing a principle based approach. The core principle of the standard is that revenue should be recognized when the transfer of promised goods or services is made in an amount that the entity expects to be entitled to in exchange for the transfer of goods and services. ASU 2014-09 also requires disclosures enabling users of financial statements to understand the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers. This standard will be effective for financial statements issued by public companies for annual reporting periods beginning after December 15, 2016. Early adoption is not permitted. The Company is currently evaluating the potential impact of ASU 2014-09 on the consolidated financial statements.
	In August 2014, the FASB issued ASU 2014-15, "Presentation of Financial Statements - Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity's Ability to Continue as a Going Concern" which describes how an entity's management should assess whether there are conditions and events that raise substantial doubt about an entity's ability to continue as a going concern within one year after the date that the financial statements are issued. Management should consider both quantitative and qualitative factors in making its assessment. The new standard applies to all entities for the first annual period ending after December 15, 2016, and for annual and interim periods thereafter. Early application is permitted. The Company will assess the potential impact of ASU 2014-15 when applicable circumstances are present.
	In November 2014, the FASB issued ASU 2014-16, "Derivatives and Hedging (Topic 815): Determining Whether the Host Contract in a Hybrid Financial Instrument Issued in the Form of a Share is More Akin to Debt or to Equity." ASU 2014-16 clarifies how current U.S. GAAP should be interpreted in evaluating the economic characteristics and risk of a host contract in a hybrid financial instrument that is issued in the form of a share. In addition, ASU 2014-16 was issued to clarify that in evaluating the nature of a host contract, an entity should assess the substance of the relevant terms and features, such as the relative strength of the debt-like or equity-like terms and features given the facts and circumstances, when considering how to weight those terms and features. The effects of initially adopting ASU 2014-16 should be applied on a modified retrospective basis to existing hybrid financial instruments issued in a form of a share as of the beginning of the fiscal year for which the amendments are effective. Retrospective application is permitted to all relevant prior periods. ASU 2014-16 is effective fiscal years, and interim periods within those fiscal years, beginning after December 15, 2015. Early adoption in an interim period is permitted. The Company will continue to determine the effects, if any, of ASU 2014-16 on its consolidated financial statements.
	New Accounting Pronouncements Issued and Adopted
	In April 2014, the FASB issued ASU 2014-08, "Presentation of Financial Statements (Topic 205) and Property, Plant, and Equipment (Topic 360): Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity." ASU 2014-08 changes the definition of a discontinued operation to include only those disposals of components of an entity representative of a strategic shift which has (or will have) a major effect on an entity's operations and financial results. In addition, ASU 2014-08 requires additional disclosures about both discontinued operations and the disposal of an individually significant component of an entity that does not qualify for discontinued operations presentation in the financial statements. The guidance is effective prospectively for fiscal years, and interim periods within those years, beginning after December 15, 2014, with early adoption permitted. We adopted the provisions of ASU 2014-08 on a prospective basis during the first quarter of fiscal year 2015. The adoption of this ASU did not have an impact on the Company's condensed consolidated financial statements.
	There are no other recently issued accounting pronouncements that are expected to have a material impact on the Company's financial condition, results of operations or cash flows.

Acquisitions_and_Divestitures

Acquisitions and Divestitures	9 Months Ended
	Jan. 31, 2015
Business Combinations [Abstract]
Acquisitions and Divestitures	ACQUISITIONS AND DIVESTITURES
	Merger Agreement with Savant Alaska, LLC
	On May 8, 2014, the Company entered into an Agreement and Plan of Merger, as amended on December 11, 2014, with Savant Alaska, LLC ("Savant") to acquire Savant, subject to due diligence and regulatory approval, for $9,000 (of which $6,000 was paid in cash and $3,000 was financed through three promissory notes in $1,000 increments, of which $1,000 was repaid as of January 31, 2015). The Company formed a wholly-owned subsidiary, Miller Energy Colorado 2014-1, LLC, which merged with Savant to facilitate the acquisition. Savant was the surviving entity upon completion of the merger, and is now a wholly-owned subsidiary of Miller. Acquisition-related costs of $396 were expensed by the Company. We recorded a net loss of $1,560 in our condensed consolidated statement of operation for the three months ended January 31, 2015 related to Savant. Miller acquired a 67.5% working interest in the Badami Unit and 100% ownership in certain nearby leases as a result of this merger. ASRC Exploration, LLC owns the remaining 32.5% working interest in the Badami Unit. In addition to the working interest in the Badami Unit and the leases, we acquired certain midstream assets located in the North Slope with a design capacity of 38,500 bopd, a 500,000 gallon diesel storage tank, 20 megawatts of power generation, a grind and inject solid waste disposal facility and Class 1 disposal well, a one mile airstrip, and two pipelines, the crude oil pipeline running approximately 25 miles in length from the Badami Unit to the Endicott Pipeline and the Duck Island Unit. Production from the Savant assets was approximately 1,000 bopd gross (600 bopd net) during January 2015.
	The transaction closed on December 11, 2014, after regulatory approval was obtained.
	The purchase of Savant has been accounted for under ASC 805, "Business Combinations." Under ASC 805, the Company is required to allocate the purchase price to assets acquired and liabilities assumed based on their fair values at the acquisition date. The estimated fair value of the properties approximates the fair value of consideration and, as a result, no goodwill was recognized. The following table summarizes the consideration paid for Savant and the allocation of the purchase price to the assets acquired and liabilities assumed which have been included in the Company's condensed consolidated financial statements. The Company is in the process of finalizing the evaluation of the assigned fair values to the assets acquired and liabilities assumed.
		Purchase Price Allocation
	Cash Consideration Paid and Promissory Notes Issued for the Acquisition:
	Cash paid	$	6,000
	Promissory notes	3,000
	Consideration paid	$	9,000
	Preliminary Allocation of Assets Acquired and Liabilities Assumed:
	Current assets	$	9,772
	Proved oil and gas properties	1,840
	Crude oil pipeline	585
	Support equipment	592
	Other assets	408
	Current liabilities	(2,757		)
	Asset retirement obligation	(1,440		)
	Fair value of assets acquired and liabilities assumed	$	9,000
	In conjunction with the acquisition of Savant, it was necessary to estimate the value of the assets acquired and liabilities assumed, which involved the use of various assumptions. The most significant assumptions, and those requiring the most judgment, involved the estimated fair value of the reserves, pipelines, and support equipment. Assumptions were also made regarding the retirement obligation. With respect to the fair values, these assumptions are considered Level 3 inputs.
	The following pro forma financial information reflects the consolidated results of our operations as if the Savant merger had occurred May 1, 2013. The pro forma information includes adjustments for operating expenses, depreciation and depletion of the acquired property and equipment, interest expense for acquisition debt and income taxes. The pro forma information is not necessarily indicative of the results of operations as it would have been had these transactions been effected on the assumed date:
		Three Months Ended January 31,						Nine Months Ended January 31,
		2015			2014			2015			2014
	Revenues	$	21,737		$	22,747		$	83,322		$	67,892
	Net loss attributable to common shareholders	$	(159,430	)	$	(5,219	)	$	(344,158	)	$	(16,622	)
	Net loss per common share, basic and diluted	$	(3.42	)	$	(0.12	)	$	(7.43	)	$	(0.38	)
	Anchor Point Pipeline Purchase
	The acquisition of the Anchor Point Pipeline closed on August 8, 2014 upon receiving approval from the Regulatory Commission of Alaska. Purchase consideration consisted of 213,586 shares of Series D Preferred Stock with a fair market value of $5,446 on August 8, 2014, which was released from escrow upon closing.
	The purchase of the Anchor Point Pipeline has been accounted for under ASC 805, "Business Combinations." Under ASC 805, the Company is required to allocate the purchase price to assets acquired and liabilities assumed based on their fair values at the acquisition date. The estimated fair value of the properties approximates the fair value of consideration and, as a result, no goodwill was recognized. The following table summarizes the consideration paid for the Anchor Point Pipeline and the allocation of the purchase price to the assets acquired and liabilities assumed which have been included in the Company's condensed consolidated financial statements. The Company is in the process of finalizing the evaluation of the assigned fair values to the assets acquired and liabilities assumed.
		Purchase Price Allocation
	Consideration Issued for Acquisition:
	Series D Preferred Stock	$	5,446
	Preliminary Allocation of Assets Acquired and Liabilities Assumed:
	Natural gas pipeline and pipeline support equipment	$	5,687
	Asset retirement obligation	(241		)
	Fair value of assets acquired and liabilities assumed	$	5,446
	In conjunction with the acquisition of the Anchor Point Pipeline, it was necessary to estimate the values of the assets acquired and liabilities assumed, which involved the use of various assumptions. The most significant assumptions, and those requiring the most judgment, involved the estimated replacement costs of the pipeline and obsolescence. Assumptions were also made regarding the retirement obligation. With respect to the fair value, these assumptions are considered Level 3 inputs.
	Acquisition-related costs included legal and other professional services charges.
	Divestiture of Tennessee Assets
	During the nine months ended January 31, 2015, the Company closed the previously announced sale of substantially all of its Tennessee oil and gas assets, including our oil and gas inventory, yielding proceeds of $4,191 in cash.

Major_Customers_and_Concentrat

Major Customers and Concentrations of Credit Risk	9 Months Ended
	Jan. 31, 2015
Risks and Uncertainties [Abstract]
Major Customers and Concentrations of Credit Risk	MAJOR CUSTOMERS AND CONCENTRATIONS OF CREDIT RISK
	For the three months ended January 31, 2015 and 2014, one customer accounted for 72% and 95%, respectively, and a second customer accounted for 19% and 0%, respectively, of Miller's consolidated total revenues. For the nine months ended January 31, 2015 and 2014, one customer accounted for 79% and 93%, respectively, and a second customer accounted for 10% and 0%, respectively, of the Company's consolidated total revenues. Two customers accounted for 14% and 11% of Miller's consolidated accounts receivable as of January 31, 2015. One customer accounted for 5% of the Company's consolidated accounts receivable as of April 30, 2014.
	Credit is extended to customers based on an evaluation of their creditworthiness and collateral is generally not required. The Company experienced no credit losses of significance during the three and nine months ended January 31, 2015 or 2014.
	The Company maintains its cash and cash equivalents (including restricted cash), which at times may exceed federally insured amounts, in highly rated financial institutions. As of January 31, 2015, the Company held $1,378 in excess of the $250 limit insured by the Federal Deposit Insurance Corporation.
	The Company has a risk of loss from counterparties not performing pursuant to the terms of their contractual obligations. The Company attempts to minimize credit-risk exposure to derivative counterparties through formal credit policies, consideration of credit ratings from public ratings agencies, monitoring procedures, master netting agreements and collateral support under certain circumstances. Collateral support could include letters of credit, payment under margin agreements and guarantees of payment by creditworthy parties. The Company also enters into master netting agreements to mitigate counterparty performance and credit risk. During the three and nine months ended January 31, 2015 and 2014, Miller did not incur any significant losses due to counterparty bankruptcy filings. The Company assesses its credit exposure on a net basis to reflect master netting agreements in place with certain counterparties. Credit exposure is offset to each counterparty with amounts the Company owes the counterparty under derivative contracts.

Related_Party_Transactions

Related Party Transactions	9 Months Ended
	Jan. 31, 2015
Related Party Transactions [Abstract]
Related Party Transactions	RELATED PARTY TRANSACTIONS
	The Company uses a number of contract labor companies to provide on demand transportation and labor at Miller's Alaska operations. H&H Industrial, Inc. ("H&H Industrial") is an entity contracted by CIE, a wholly-owned subsidiary of the Company, to provide services related to the exploration and production of oil and natural gas. H&H Industrial is owned by immediate family members of David Hall, the Company's Chief Operating Officer ("COO"). For the three and nine months ended January 31, 2015, the Company recorded capital and lease operating expenses related to H&H Industrial of $617 and $2,320, respectively. The Audit Committee of Miller's Board of Directors determined that the amounts paid by the Company for the services performed were fair and in the best interest of the Company.
	On December 9, 2014, the Company entered into a two-year consulting agreement (subject to approval by the Compensation Committee of our Board of Directors which occurred on March 9, 2015) with Deloy Miller under which he agreed to assist with its oil and gas related matters, including assisting with the Company's strategic planning, providing management with drilling advice, and other consulting services the Company may reasonably request. As compensation for these services, the Company agreed to pay Mr. Miller $275 per year and granted Mr. Miller an option to purchase 100,000 shares of its common stock at an exercise price of $1.35 per share, vesting in equal installments on the first and second anniversary of the date the parties entered into the consulting agreement. In addition, the Company has agreed to assign over to Mr. Miller a life insurance policy covering Mr. Miller, with respect to which the Company is currently listed as beneficiary. When assigned, Mr. Miller would be free to designate a new beneficiary; however, the Company would continue to pay the premiums on this policy until the expiration of the two-year term of our consulting agreement with him. Mr. Miller is a related party to the Company as a result of his former employment with the Company and his relationship to Mr. Boruff, the Company's Executive Chairman, as his former father-in-law. The Audit Committee of the Company's Board of Directors determined that the consideration given by the Company for the services to be performed was fair and entering into the agreement was in the best interest of the Company.

Oil_and_Gas_Properties_and_Equ

Oil and Gas Properties and Equipment	9 Months Ended
	Jan. 31, 2015
Property, Plant and Equipment [Abstract]
Oil and Gas Properties and Equipment	OIL AND GAS PROPERTIES AND EQUIPMENT
	Oil and gas properties (successful efforts method) are summarized as follows:
		January 31,			April 30,
		2015			2014
	Property costs:
	Proved property	$	476,694		$	467,740
	Unproved property	47,984			243,230
	Total property costs	524,678			710,970
	Less: Accumulated depletion	(334,956		)	(66,143		)
	Oil and gas properties, net	$	189,722		$	644,827
	On January 31, 2015, the significant and continued decline in crude oil prices during the third quarter of fiscal 2015 was identified as an impairment-related triggering event for proved properties. The Redoubt Unit and West McArthur River Unit failed the step 1 test which is based on undiscounted cash flows. The failure of step 1 required the Company to measure the estimated fair value of the Redoubt Unit and the West McArthur River Unit based on discounted cash flows. The step 2 analysis resulted in an impairment to proved and unproved properties of the Redoubt Unit and West McArthur River Unit of $81,480 and $67,586, respectively. The factors used to estimate the fair value of the Redoubt Unit and the West McArthur River Unit include, but are not limited to, estimates of reserve quantities, future commodity prices, the timing of future production, operating costs, capital expenditures and a risk adjusted discount rate. Because these significant fair value inputs are typically not observable, the Company has categorized the amounts as Level 3 inputs. As of January 31, 2015, the proved and unproved properties of the Redoubt Unit were written down to their estimated fair value of $42,044 and $2,318, respectively. Also as of January 31, 2015, the proved and unproved properties of the West McArthur River Unit were written down to their estimated fair value of $75,433 and $1,252, respectively. Also during the third quarter of fiscal 2015, the Company recorded a charge to exploration expense of $40,443 for other unproved properties, including Olson Creek #1 and Otter #1 due to changes in our drilling plans.
	On October 31, 2014, the significant decline in crude oil prices during the second quarter of fiscal 2015 was identified as an impairment-related triggering event for proved and unproved properties. The Redoubt Unit failed the step 1 test which is based on undiscounted cash flows. The failure of step 1 required the Company to measure the estimated fair value of the Redoubt Unit based on discounted cash flows. The step 2 analysis resulted in an impairment to proved and unproved properties of the Redoubt Unit of $112,414 and $152,887, respectively. The factors used to estimate the fair value of the Redoubt Unit include, but are not limited to, estimates of reserve quantities, future commodity prices, the timing of future production, operating costs, capital expenditures and a risk adjusted discount rate. Because these significant fair value inputs are typically not observable, the Company has categorized the amounts as Level 3 inputs.
	During the second and third quarters of fiscal 2015, the Company recorded a charge to exploration expense of $18,800 for Olson Creek #2, which was determined to be a dry hole. In addition, on October 31, 2014, we recognized an impairment of $1,319 to write down the net assets of substantially all of our Tennessee oil and gas properties to reflect the expected sales price. These properties were sold on November 20, 2014. During the fiscal third quarter, we recognized an impairment of $4,205 to write down certain Tennessee-related assets classified as held for sale as of January 31, 2015 that remained subsequent to the sale of substantially all of our Tennessee oil and gas properties to reflect the expected respective sales price of those assets.
	Equipment is summarized as follows:
		January 31,			April 30,
		2015			2014
	Machinery and equipment	$	2,821		$	7,759
	Vehicles	1,425			1,877
	Buildings	2,043			2,726
	Office equipment	1,054			1,108
	Leasehold improvements	676			527
	Drilling rigs	44,581			30,210
	Capital lease asset	4,022			1,500
	Pipeline and pipeline support assets	6,255			—
		62,877			45,707
	Less: Accumulated depreciation	(11,186		)	(10,338		)
	Equipment, net	$	51,691		$	35,369
	The Company classified its aircraft as an asset held for sale on the condensed consolidated balance sheets as of April 30, 2014 and January 31, 2015. The aircraft is recorded at estimated fair value less cost to sell.
	During the nine months ended January 31, 2015, substantially all of the remaining portion of the Company's Tennessee assets were reclassified and presented as assets held for sale. The Company estimates the fair value of these assets and liabilities to be $2,331 and $950, respectively. An impairment charge of $5,524 was recorded during the nine months ended January 31, 2015, representative of the excess of the assets carrying value over the estimated fair value less cost to sell. Because these significant fair value inputs are typically not observable, the Company has categorized the amounts as Level 3 inputs.
	Depreciation, depletion and amortization consisted of the following:
		For the Nine Months Ended January 31,
		2015			2014
	Depletion of oil and gas related assets	$	53,240		$	19,158
	Depreciation and amortization of equipment	3,361			3,194
	Total	$	56,601		$	22,352
	The Company has obtained multiple reserve reports in the last twelve months due to Miller's acquisition and drilling activity in Alaska. The reserve reports have provided incremental information to allow the Company to better understand the reserves on a field basis. These changes in reserve estimates have caused an increase in proved property depletion.
	Entry into Glacier Rig Purchase Option
	Effective as of July 4, 2014, the Company entered into a Purchase and Sale Agreement with Teras Oilfield Support Limited which granted Miller the right to purchase the Glacier Drilling Rig #1, a Mesa 1000 carrier-mounted land drilling rig, which Miller has renamed Rig 37, and related equipment. During the nine months ended January 31, 2015, the Company paid $7,000 in connection with the acquisition of Rig 37.
	Acquisition of Rig 36 and Related Capital Lease
	On May 5, 2014, the Company entered into a Rig Equipment Purchase Agreement with Baker Process, Inc. to purchase a 2400 HP rig, which Miller has named Rig 36, and related equipment. On May 9, 2014, the Company entered into a capital lease with First National Capital, LLC to finance the purchase of and planned future modifications to Rig 36. The Company has drawn $3,250 under the capital lease.

Derivative_Instruments

Derivative Instruments	9 Months Ended
	Jan. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments	DERIVATIVE INSTRUMENTS
	Derivative Instruments
	Commodity Derivatives
	From time to time, the Company enters into derivative financial instruments to mitigate its exposure to crude oil price volatility. The derivative financial instruments, which are placed with financial institutions that the Company believes are acceptable credit risks, take the form of over-the-counter variable-to-fixed price commodity swaps. All derivative financial instruments are recognized in the Company's condensed consolidated financial statements at fair value. The fair values of Miller's derivative instruments are determined based on discounted cash flows derived from quoted forward prices. The Company does not use hedge accounting for commodity derivatives; thus, the open positions are recorded at fair value with the change in value recorded to earnings.
	Miller has experienced, and could continue to experience, earnings volatility due to fluctuations in the fair value of these commodity derivative contracts. Miller's reported cash flows are affected by cash settlements, and its results of operations are affected by the volatility of mark-to-market gains and losses and changes in fair value, which fluctuate with changes in crude oil prices. These fluctuations could be significant in a volatile pricing environment.
	As of January 31, 2015, the Company had the following open crude oil derivative positions. All are priced based on the Brent crude oil futures as traded on the Intercontinental Exchange.
			Fixed - Price Swaps
	Production Period ending April 30,		Bbls			Weighted Average Fixed Price
	2015		191,400			$	97.09
	2016		787,600			$	95.36
	2017		232,600			$	93.97
	Derivative Activities Reflected on Condensed Consolidated Balance Sheets
	The following table presents the fair value of commodity derivatives. The fair value amounts are presented on a gross basis and do not reflect the netting of asset and liability positions permitted under the terms of Miller's master netting arrangements.
			Asset Derivatives											Liability Derivatives
			January 31, 2015						April 30, 2014					January 31, 2015				April 30, 2014
	Derivatives not designated as hedging instruments under ASC 815		Balance Sheet Location		Fair Value				Balance Sheet Location		Fair Value			Balance Sheet Location		Fair Value		Balance Sheet Location	Fair Value
	Commodity derivatives		Short-term portion of derivative instruments		$	29,513			Short-term portion of derivative instruments		$	88		Short-term portion of derivative instruments		$	—	Short-term portion of derivative instruments	$	(3,315	)
	Commodity derivatives		Long-term portion of derivative instruments		12,027				Long-term portion of derivative instruments		26			Long-term portion of derivative instruments		—		Long-term portion of derivative instruments	(4,006		)
	Total derivatives not designated as hedging instruments under ASC 815				$	41,540					$	114				$	—		$	(7,321	)
	Offsetting of Derivative Assets and Liabilities
	The following table presents the Company's gross and net derivative assets and liabilities:
		Gross Amount Presented on Balance Sheet				Netting Adjustments (a)				Net Amount
	January 31, 2015
	Derivative assets with right of offset or master netting agreements	$	41,540			$	—			$	41,540
	April 30, 2014
	Derivative assets with right of offset or master netting agreements	$	114			$	(114	)		$	—
	Derivative liabilities with right of offset or master netting agreements	$	(7,321	)		$	114			$	(7,207	)
	—————————
	(a)	The Company has an agreement in place that allows for the financial right of offset for derivative assets and derivative liabilities at settlement or in the event of default under the agreement.
	Derivative Activities Reflected on Condensed Consolidated Statements of Operations
	Gains and losses on derivatives are reported in the condensed consolidated statements of operations. The following represents the Company's reported gains and losses on derivative instruments for the periods presented:
		For the Three Months Ended January 31,								For the Nine Months Ended January 31,
		2015				2014				2015			2014
	Gain (loss) on derivatives, net	$	39,330			$	1,677			$	55,516		$	(5,589	)
	As of January 31, 2015, Miller did not maintain any derivative instruments that were classified as fair value hedges or trading securities. In addition, as of January 31, 2015, the Company did not maintain any derivative instruments containing credit risk contingencies.

Fair_Value_Measurements

Fair Value Measurements	9 Months Ended
	Jan. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTS
	Fair Value Measurement on a Recurring Basis
	The carrying amounts reported in the condensed consolidated balance sheets for cash and cash equivalents, trade receivables, account payables and other short-term liabilities approximate fair value due to the nature of the instrument and/or the short-term maturity of these instruments. Other fair value measurements are noted throughout the Notes to the Condensed Consolidated Financial Statements and the level of inputs classified. The fair values of the Company's commodity derivative instruments are classified as Level 2 measurements as they are calculated using industry standard models using assumptions and inputs which are substantially observable in active markets throughout the full term of the instruments. These include market price curves, contract terms and prices, credit risk adjustments, and discount factors. The following summarizes the fair value of the Company's commodity derivative assets and liabilities according to their fair value hierarchy as of the reporting dates indicated:
		Fair Value Measurements
	At January 31, 2015	Level 1		Level 2			Level 3
	Commodity derivative asset	$	—	$	41,540		$	—
	Commodity derivative liability	—		—			—
	Total	$	—	$	41,540		$	—
	At April 30, 2014
	Commodity derivative asset	$	—	$	114		$	—
	Commodity derivative liability	—		(7,321		)	—
	Total	$	—	$	(7,207	)	$	—
	There were no transfers between Level 1, Level 2 or Level 3 during the nine months ended January 31, 2015.

Debt

Debt	9 Months Ended
	Jan. 31, 2015
Debt Disclosure [Abstract]
Debt	DEBT
	As of January 31, 2015 and April 30, 2014, the Company had the following debt obligations:
		January 31,				April 30,
		2015				2014
	Second Lien Credit Facility	$	175,000			$	175,000
	Debt discount related to Second Lien Credit Facility	(2,639		)		(3,296		)
	First Lien RBL	44,000				—
	Savant Promissory Notes payable	2,000				—
	Gunsight Promissory Note payable	—				950
	Apollo prepayment and extension fee note payable	2,306				9,223
	Capital lease obligation	2,756				—
	Series B Preferred Stock	2,382				2,325
	Total debt obligations	225,805				184,202
	Less: Current maturities	(29,553		)		(9,459		)
	Total debt less current maturities	$	196,252			$	174,743
	As of January 31, 2015, the Company's current maturities of long term debt related to amounts that are due to our lenders within the next twelve months in accordance with provisions in the underlying agreements.
	Second Lien Credit Facility
	On February 3, 2014, the Company refinanced its $100,000 credit facility with Apollo Investment Corp. ("Apollo") (the "Prior Credit Facility") by entering into a new Credit Agreement (as amended, the "Second Lien Credit Agreement") among the Company, as borrower, Apollo, as administrative agent (in that capacity, the "Second Lien Agent"), and Apollo and certain affiliates of Highbridge Capital Strategies (the "Second Lien Lenders") which set forth the terms of a credit facility of $175,000 (as amended, the "Second Lien Credit Facility").
	The Second Lien Credit Agreement provides for a $175,000 term credit facility, all of which was made available to and drawn by the Company on the closing date. The amounts drawn were subject to a 2% original issue discount. Absent an event of default, amounts outstanding under the Second Lien Credit Facility bear interest at a rate of LIBOR plus 9.75%, subject to a 2% LIBOR floor. Under the terms of the Second Lien Credit Facility, Miller was permitted to enter into a reserve-based revolving credit facility on certain agreed terms which would be secured on a first-lien basis. Upon entering into such revolving credit facility and a related intercreditor agreement, the Second Lien Credit Facility would become a second-lien credit facility. The Company entered into a credit agreement for a revolving credit facility (the "First Lien Loan Agreement"), among the Company, as borrower, KeyBank National Association ("KeyBank"), as administrative agent (in that capacity the "RBL Administrative Agent"), and the lenders from time to time party thereto (the "RBL Lenders") on June 2, 2014. The First Lien Loan Agreement provides for a senior secured, reserve-based revolving credit facility of up to $250,000 (the "First Lien RBL"). In connection with the Company's entry into the First Lien Loan Agreement, we amended the Second Lien Credit Agreement. The Second Lien Credit Facility carries a four year maturity. The Second Lien Credit Facility contains covenants, including but not limited to, a leverage ratio, interest coverage ratio, current ratio, asset coverage ratio, minimum gross production and change of management control covenants, as well as other covenants customary for a transaction of this type. As of January 31, 2015, there was an event of default under the Second Lien Credit Facility arising from a delay in our issuing a mortgage in favor of the Second Lien Lenders covering a right-of-way lease underlying our North Fork Pipeline (the "Second Lien Technical Default"). Additionally, the Company was not in compliance with certain of the required financial covenants as of January 31, 2015 (the "Second Lien Covenant Default"), although the Company was in compliance with the production covenant and other covenants. The Second Lien Technical Default and Second Lien Covenant Default were waived or otherwise remedied by the March 2015 Second Lien Amendment (as defined below under Note 16, Subsequent Events). While we believe we will comply with the covenants in the Second Lien Credit Facility for the next twelve months, if we are unable to do so or are unable to obtain a waiver from our lender, our debt would become immediately due and payable and we would not be able to utilize our assets to satisfy our obligations.
	The Company used $75,306 of the proceeds drawn under the Second Lien Credit Facility to refinance the Prior Credit Facility with Apollo and $56,577 to finance the acquisition of the North Fork unit. In addition, $3,071 was used to retire the obligations owed under the MEI loan documents. The remainder of the proceeds from the Second Credit Facility were used for general corporate purposes. The fair value of the outstanding balance of the Second Lien Credit Facility was $171,525 and $176,785 as of January 31, 2015 and April 30, 2014, respectively, as calculated using the discounted cash flows method. Level 3 inputs were used to calculate the fair value of the outstanding balance of the Second Lien Credit Facility.
	On the closing date, in connection with the Second Lien Credit Facility, the Company, along with all of its then consolidated subsidiaries (other than MEI), entered into an Amended and Restated Guarantee and Collateral Agreement (the "Second Lien Guarantee") with Apollo, for the benefit of the lenders from time to time party to the Second Lien Credit Agreement. Under the terms of the Second Lien Guarantee and related security documents, each of the Company's consolidated subsidiaries (other than MEI and Nutaaq Pipeline, LLC) have guaranteed our obligations under the Second Lien Credit Facility and we and those subsidiaries have granted a security interest in substantially all of their assets to secure the performance of the obligations arising under the Second Lien Credit Facility.
	On June 2, 2014, the Company entered into the Amendment No. 1 to Credit Agreement and Guarantee and Collateral Agreement to the Second Lien Credit Facility and the Second Lien Guarantee. This amendment conforms certain of the covenants, terms and conditions in the Second Lien Credit Facility to match those of the First Lien RBL, including the financial covenants.
	On August 11, 2014, the Company entered into Amendment No. 2 to the Second Lien Credit Agreement, which amended a default provision to remove its reference to David Voyticky, our former president. Prior to this amendment, under the Second Lien Credit Agreement, the resignation of Mr. Voyticky would have been a default. In addition, this amendment removed references to Mr. Voyticky from certain defined terms used in the Second Lien Credit Agreement.
	On August 19, 2014, the Company entered into Amendment No. 3 to the Second Lien Credit Agreement, which (i) increased the total amount of obligations we may enter into under capital leases from time to time, (ii) allowed us to make certain investments in Savant, and (iii) increased the amount of preferred stock that we may issue, among other things.
	On December 10, 2014, the Company entered into Waiver and Amendment No. 4 to Credit Agreement and Amendment No. 2 to Guarantee and Collateral Agreement (the "December Second Lien Amendment") to our Second Lien Credit Agreement and our Second Lien Guarantee. The December Second Lien Amendment, among other things, (1) makes conforming amendments to our leverage and interest covenants, matching those in the December First Lien Amendment (as defined below), (2) establishes approved plans of development (the "Plans"), defines "Permitted Capital Expenditures," adds requirements for the development of our drilling program with those Plans and restricts our ability to engage in capital expenditures other than Permitted Capital Expenditures, (3) permits us to issue an additional $25,000 in preferred stock, measured in terms of the stated liquidation preference of that stock (as with the December First Lien Amendment, up to $50,000 in stated liquidation preference in total), (4) adjusts the percentage by value of our oil and gas properties that must be the subject of mortgages in favor of the Second Lien Agent (for the benefit of the Second Lien Lenders) from 80% to 90%, (5) includes Mr. Carl F. Giesler, Jr., our Chief Executive Officer, as one of the officers designated in the definition of "Change of Control" under the Second Lien Credit Agreement, (6) eliminates restrictions on the sale of equity interests by Mr. Deloy Miller without impacting the "Change of Control" definition therein, (7) provides waivers related to certain events of default which arose as a result of Mr. Scott M. Boruff’s resignation as our Chief Executive Officer and certain sales of equity interests by Mr. Boruff as well as in connection with a scheduled payment of dividends on our preferred stock that occurred while an event of default had occurred; (8) extends the date by which the Company must remediate the material weakness in its internal controls over financial reporting from April 30, 2015 to April 30, 2016, (9) waives the requirement that the proceeds of the sale of (i) certain miscellaneous oil and gas equipment and office supplies in Tennessee or (ii) interests in the oil and gas properties of Savant, be applied to prepay the loans under the Second Lien Credit Agreement, so long as those proceeds are applied to certain projects specified in the Plans, (10) makes certain technical amendments intended to allow us to close the acquisition of Savant by easing certain requirements (which would have applied after that acquisition in the absence of the December Second Lien Amendment) related to its subsidiary, Nutaaq Pipeline, LLC, (11) increases the interest rate applicable to loans under the Second Lien Credit Agreement by 1% per annum (or, if the Company elects to pay such interest in kind, by 2% per annum) until the Company has raised $20,000 in net proceeds from the issuance of equity interests of the Company, provided that if the Company has not raised such amounts within four months, the change in the interest rate becomes permanent and (12) adds additional events of default.
	First Lien RBL
	On June 2, 2014, Miller entered into the First Lien Loan Agreement, among the Company, as borrower, KeyBank, as the RBL Administrative Agent, and the RBL Lenders. In addition to KeyBank, the syndicate includes CIT Finance LLC, Mutual of Omaha Bank and OneWest Bank N.A.
	The First Lien Loan Agreement provides for a $250,000 senior secured, reserve-based revolving credit facility, $60,000 of which was made available to the Company on the closing date. The borrowing base will be redetermined semi-annually on February 1st and August 1st of each year. Amounts outstanding under the First Lien RBL are priced on a sliding scale, based on LIBOR plus 300 to 400 basis points, depending upon the level of borrowing (per the table below).
	Borrowing Base Utilization Grid
	Borrowing base utilization percentage	<25%	≥ 25%, but <50%	≥ 50%, but <75%	≥ 75%, but <90%	≥ 90%, but ≤100%
	Spread above LIBOR	3.00%	3.25%	3.50%	3.75%	4.00%
	Undrawn commitment fee rate	0.50%	0.50%	0.75%	0.75%	0.75%
	The First Lien RBL will expire on the third anniversary of its closing. It contains customary covenants, including, but not limited to, a leverage, interest coverage, current ratio, minimum gross production, minimum liquidity, asset coverage and change of management control covenants.  Due to the existence of the Second Lien Technical Default which arose due to a delay in our issuing mortgage in favor of the Second Lien Lenders coving a right-of-way lease underlying our North Fork Pipeline, there was an event of default under the First Lien Loan Agreement's cross default provision (the "First Lien Technical Default"). Additionally, the Company was not in compliance with (1) a related covenant to issue a mortgage covering that right-of-way lease in favor of the RBL Lenders and (2) certain of the required financial covenants as of January 31, 2015 (the "First Lien Covenant Default"), although the Company was in compliance with the production covenant and other covenants. While we believe we will comply with the covenants in the First Lien Credit Facility for the next twelve months, if we are unable to do so or are unable to obtain a waiver from our lender, our debt would become immediately due and payable and we would not be able to utilize our assets to satisfy our obligations. The First Lien Technical Default and First Lien Covenant Default were waived or otherwise remedied by the March 2015 First Lien Amendment (as defined below in Note 16, Subsequent Events).
	The Company drew $20,000 on the closing date under the First Lien RBL, which was used to provide working capital for development drilling in Alaska. The amounts available were subject to an upfront fee equal to 1% of the initial borrowing base. On June 20, 2014, Miller requested an additional $10,000, which was funded on June 24, 2014. On August 1, 2014, the Company drew down $16,000. On December 11, 2014, the Company drew $3,000 down and an additional $5,000 on December 31, 2014. The Company repaid borrowings of $10,000 during the nine months ended January 31, 2015. The fair value of floating-rate debt approximates the carrying amount because the interest rates paid are based on short-term maturities.
	Also on June 2, 2014, in connection with the First Lien RBL, the Company, along with all of its then consolidated subsidiaries (other than MEI and Miller Energy Colorado 2014-1, LLC), entered into a First Lien Guarantee and Collateral Agreement (the "First Lien Guarantee") with KeyBank, for the benefit of the RBL Lenders from time to time party to the First Lien Loan Agreement. Under the terms of the First Lien Guarantee and related security documents, each of the Company's consolidated subsidiaries (other than MEI and Nutaaq Pipeline, LLC) have guaranteed the obligations under the First Lien RBL. Along with the aforementioned subsidiaries, Miller has granted a security interest in substantially all of its assets to secure the performance of the obligations arising under the First Lien RBL.
	On August 11, 2014, the Company entered into the First Amendment to our First Lien Loan Agreement, which amended a default provision to remove its reference to Mr. Voyticky. Prior to this amendment, under the First Lien Loan Agreement, the resignation of Mr. Voyticky would have been a default. In addition, this amendment removes references to Mr. Voyticky from certain defined terms used in the First Lien Loan Agreement.
	On August 19, 2014, the Company entered into the Second Amendment to our First Lien Loan Agreement, which (i) increases the total amount of obligations we may enter into under capital leases from time to time, (ii) allows us to make certain investments in Savant, and (iii) increases the amount of preferred stock that we may issue, among other things.
	On December 10, 2014, the Company entered into a Third Amendment (the "December First Lien Amendment") to the First Lien Credit Agreement and the First Lien Guarantee. The December First Lien Amendment, among other things, (1) amends our leverage and interest covenants, (2) establishes the Plans, defines "Permitted Capital Expenditures," adds requirements for the development of the our drilling program within those Plans and restricts our ability to engage in capital expenditures other than Permitted Capital Expenditures, in each case in a manner consistent with the December Second Lien Amendment, (3) permits us to issue an additional $25,000 in preferred stock, measured in terms of the stated liquidation preference of that stock (up to $50,000 in stated liquidation preference in total), (4) adjusts the percentage by value of our oil and gas properties that must be the subject of mortgages in favor of the RBL Administrative Agent (for the benefit of the RBL Lenders) from 80% to 90%, (5) includes Mr. Carl F. Giesler, Jr., our Chief Executive Officer, as one of the officers designated in the definition of "Change of Control," (6) eliminates restrictions on the sale of equity interests by Mr. Deloy Miller without impacting that "Change of Control" definition, (7) provides waivers related to certain events of default which arose as a result of Mr. Scott M. Boruff’s resignation as our Chief Executive Officer and certain sales of equity interests by Mr. Boruff as well as in connection with the scheduled payment of dividends on our preferred stock that occurred while an event of default had occurred, (8) extends the date by which the Company must remediate the material weakness in its internal controls over financial reporting from April 30, 2015 to April 30, 2016, but requires an additional borrowing base redetermination, unless waived by the majority of the RBL Lenders, in the event our April 30, 2015 audited financial statements are issued with any qualification as to the effectiveness of our internal controls over financial reporting, (9) makes certain technical amendments intended to allow us to close the acquisition of Savant by easing certain requirements (which would have applied after that acquisition in the absence of this First Lien Amendment) related to its subsidiary, Nutaaq Pipeline, LLC, (10) requires that we not permit the aggregate revolving credit exposure of the RBL Lenders to exceed $50,000 in the aggregate prior to next redetermination date for our borrowing base, scheduled for February 1, 2015 and (11) required that, following receipt of our tax credit payment from the State of Alaska in February of 2015, we not allow the aggregate revolving credit exposure of the RBL Lenders to exceed $40,000.
	Savant Promissory Notes Payable
	As merger consideration for the Savant acquisition, three $1,000 promissory notes were issued to the former owners of Savant Alaska, LLC. The notes mature on December 18, 2014, February 28, 2015 and June 30, 2015. The Company had $2,000 of promissory notes outstanding at January 31, 2015. The December 18, 2014 promissory note was paid and, subsequent to January 31, 2015, the February 28, 2015 promissory note was paid. These promissory notes do not bear any interest if paid on or before the maturity date. Any payment of the promissory note not paid on or before the maturity date shall bear interest at the default interest rate of 1.5% per month. No interest has been paid on the promissory notes.
	Series B Preferred Stock
	The outstanding Series B Preferred Stock is classified as long-term debt in accordance with ASC 480, "Distinguishing Liabilities from Equity." As of January 31, 2015 and April 30, 2014, the fair value of Series B Preferred Stock was $2,075 and $2,197, respectively, as calculated using the discounted cash flow method. The fair value of the Series B Preferred Stock is classified as a Level 3 measurement as the fair value is calculated using a discounted cash flow model.
	The following table summarizes the Series B Preferred Stock dividend activity for the nine months ended January 31, 2015.
	Series		Declaration Date		Dividend per Share				Annualized Percentage Rate		Par Value		Accrual Period	Record Date	Payment Date
	B		July 28, 2014		$	6.05			12	%	$	100	Mar. 1 - Aug. 31, 2014	August 15, 2014	September 2, 2014
	B		January 30, 2015		$	5.95			12	%	$	100	Sept. 1, 2014 - Feb. 28, 2015	February 13, 2015	March 2, 2015
	Debt Issue Costs
	As of January 31, 2015 and April 30, 2014, the Company's unamortized deferred financing costs were $3,364 and $803, respectively, which relates to the First Lien RBL and the Second Lien Credit Facility. These costs are being amortized over the term of the respective debt instruments.

Asset_Retirement_Obligations

Asset Retirement Obligations	9 Months Ended
	Jan. 31, 2015
Asset Retirement Obligation Disclosure [Abstract]
Asset Retirement Obligations	ASSET RETIREMENT OBLIGATIONS
	The following table presents changes to the Company's asset retirement obligation ("ARO") liability for the nine months ended January 31, 2015 and 2014:
		2015			2014
	Asset retirement obligation, as of April 30,	$	22,872		$	19,890
	Additions	2,206			196
	Revisions	(100		)	—
	Sold wells	(1,495		)	—
	Accretion expense	1,067			903
	Settlements	(121		)	(22		)
	North Fork properties purchase price adjustment	159			—
	Asset retirement obligation, as of January 31,	$	24,588		$	20,967
	The ARO liability reflects the estimated present value of the amount of dismantlement, removal, site reclamation, and similar activities associated with the Company's oil and gas properties. The Company utilizes current retirement costs to estimate the expected cash outflows for retirement obligations. The Company estimates the ultimate productive life of the properties, a risk-adjusted discount rate, and an inflation factor in order to determine the current present value of this obligation. To the extent future revisions to these assumptions impact the present value of the existing ARO liability, a corresponding adjustment is made to the oil and gas property balance.
	Any additional retirement obligations will increase the liability associated with new oil and natural gas wells and other facilities. Actual expenditures for abandonments of oil and natural gas wells and other facilities reduce the liability for asset retirement obligations.

StockBased_Compensation

Stock-Based Compensation	9 Months Ended
	Jan. 31, 2015
Share-based Compensation [Abstract]
Stock-Based Compensation	STOCK-BASED COMPENSATION
	During fiscal years 2010 and 2011, the Company's Compensation Committee and Board of Directors adopted share-based compensation plans authorizing 3,000,000 and 8,250,000 shares of common stock under each plan, respectively. On April 16, 2014, the number of shares of common stock available for issuance increased by 5,000,000 shares of common stock under the 2011 Equity Compensation Plan (the "2011 Plan"). The amendment to the 2011 Plan providing for the increase was adopted by the Company's Board of Directors on March 10, 2014, and approved by its shareholders on April 16, 2014. On October 30, 2014, the number of shares of common stock available for issuance increased by 2,500,000 shares of common stock under the 2011 Plan. The amendment to the 2011 Plan providing for the increase was adopted by the Company's Board of Directors on September 14, 2014, and approved by its shareholders on October 30, 2014. The share-based compensation plans allow Miller to offer its employees, officers, directors and others an opportunity to acquire a proprietary interest in the Company and enables the Company to attract, retain, motivate and reward such persons in order to promote its success. Each plan authorizes the issuance of incentive stock options, nonqualified stock options and restricted stock.  All awards issued under the share-based compensation plans must be approved by the Company's Compensation Committee. At January 31, 2015 and April 30, 2014, there were 187,500 and 2,500 shares available under the 2010 Miller Petroleum, Inc. Stock Plan, respectively, and 3,157,256 and 3,132,078 additional shares available under the 2011 Plan, respectively.
	Allocated between general and administrative expenses and cost of oil and gas sales within the condensed consolidated statements of operations is stock-based compensation expense for the three and nine months ended January 31, 2015 of approximately $703 and $10,242, respectively, and $1,343 and $4,368 for the three and nine months ended January 31, 2014, respectively. The Company also recognized non-employee expense related to warrants issued for the three and nine months ended January 31, 2015 of approximately $41 and $615, respectively, and $203 and $752 for the three and nine months ended January 31, 2014, respectively.
	The following table summarizes stock options and warrants activity for the period presented:
		Number of Options and Warrants		Weighted Average Exercise Price
	Beginning balance at April 30, 2014	15,021,347		$	4.99
	Granted	2,720,500		4.53
	Exercised	(329,939	)	4.37
	Cancelled	(1,380,460	)	4.95
	Ending balance	16,031,448		4.93
	Options and warrants exercisable at January 31, 2015	13,760,634		$	4.96
	The following table summarizes stock options and warrants outstanding, including exercisable shares at January 31, 2015:
	Options and Warrants Outstanding							Options and Warrants
								Exercisable
	Range of Exercise Price		Number Outstanding		Weighted Average Remaining Contractual Life (in years)	Weighted Average Exercise Price		Number Exercisable	Weighted Average Exercise Price
	$0.01 to $1.24		1,361,000		1.3	$	0.63	1,311,000	$	0.61
	$2.00 to $4.99		3,673,001		7	4.04		2,227,687	3.77
	$5.15 to $5.53		4,137,447		2.2	5.32		3,641,947	5.33
	$5.68 to $5.94		3,435,000		5.8	5.9		3,195,000	5.92
	$6.00 to $6.95		3,425,000		1.9	6.13		3,385,000	6.12
			16,031,448		3.9	$	4.93	13,760,634	$	4.96
	The following table summarizes restricted stock activity for the nine months ended January 31, 2015:
	Unvested at April 30, 2014	465,432
	Granted	945,655
	Vested	(1,182,587	)
	Cancelled	(28,000	)
	Unvested at January 31, 2015	200,500

Stockholders_Equity

Stockholders' Equity	9 Months Ended
	Jan. 31, 2015
Stockholders' Equity Note [Abstract]
Stockholders' Equity	STOCKHOLDERS' EQUITY
	Common Stock
	At January 31, 2015, the Company had 46,662,223 shares of common stock outstanding. The Company issued 905,526 shares during the nine months ended January 31, 2015, of which 575,587 shares were issued to employees for compensation, and 329,939 shares were related to the exercise of equity rights.
	Series C Preferred Stock
	During the nine months ended January 31, 2015, the Company sold 180,032 shares of its 10.75% Series C Cumulative Redeemable Preferred Stock (the "Series C Preferred Stock"), with a redemption value of $25.00 per share, pursuant to an "at-the-market" offering, yielding net proceeds of $1,799. The dividend yield on these "at-the-market" shares is 27% and the redemption amount is $4,583.
	Series D Preferred Stock
	During the nine months ended January 31, 2015, the Company sold 1,296,574 shares of its 10.5% Series D Fixed Rate/Floating Rate Cumulative Redeemable Preferred Stock (the "Series D Preferred Stock"), with a redemption value of $25.00 per share, pursuant to an "at-the-market" offering, yielding net proceeds of $11,753. The dividend yield on these "at-the-market" shares is 29% and the redemption amount is $32,698.
	On August 25, 2014, the Company completed and closed a public offering of its 10.5% Series D Preferred Stock with a liquidation preference of $25.00 per share. The Company issued 750,000 shares which were offered to the public at $24.50 per share for gross proceeds of $18,375. The Company incurred issuance costs of $1,352, yielding net proceeds of $17,023.
	Dividends Declared on Preferred Stock
	The following table summarizes the Series C Preferred Stock and Series D Preferred Stock dividend activity for the nine months ended January 31, 2015.
	Series	Declaration Date	Dividend per Share		Annualized Percentage Rate		Par Value		Accrual Period	Record Date	Payment Date
	C	July 28, 2014	$	0.67	10.75	%	$	25	Jun. 1 - Aug. 31, 2014	August 15, 2014	September 2, 2014
	D	July 28, 2014	$	0.66	10.5	%	$	25	Jun. 1 - Aug. 31, 2014	August 15, 2014	September 2, 2014
	C	October 29, 2014	$	0.67	10.75	%	$	25	Sept. 1 - Nov. 30, 2014	November 14, 2014	December 1, 2014
	D	October 29, 2014	$	0.66	10.5	%	$	25	Sept. 1 - Nov. 30, 2014	November 14, 2014	December 1, 2014
	C	January 30, 2015	$	0.67	10.75	%	$	25	Dec. 1, 2014 - Feb. 28, 2015	February 13, 2015	March 2, 2015
	D	January 30, 2015	$	0.66	10.5	%	$	25	Dec. 1, 2014 - Feb. 28, 2015	February 13, 2015	March 2, 2015
	Fair Value Measurements
	The estimated fair value of the Company's Series C and Series D Preferred Stock was $41,373 and $36,670, respectively, as of January 31, 2015, and $77,976 and $31,330, respectively, as of April 30, 2014.

Income_Taxes

Income Taxes	9 Months Ended
	Jan. 31, 2015
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES
	Under ASC 740, companies are required to assess whether a valuation allowance should be established against their deferred tax assets based on the consideration of all available evidence using a "more likely than not" standard. In making such judgments, significant weight is given to evidence that can be objectively verified. We are in a three year cumulative pre-tax loss position as of January 31, 2015. A cumulative loss position is considered significant negative evidence in assessing the realizability of a deferred tax asset and is difficult to overcome. We did not consider future taxable income, tax planning strategies, or income in carry back years in determining the realizability of our deferred tax assets. Our estimate of the realization of the deferred tax assets was solely based on future reversals of existing taxable temporary differences. This resulted in the imposition of an additional valuation allowance of approximately $64,273 during the nine months ended January 31, 2015. Our provision for income taxes is based on the actual year-to-date effective rate, which includes the adjustment for the increase in the valuation allowance, as this is our best estimate of our annual effective tax rate for the full fiscal year. The computation of the annual effective tax rate includes a forecast of our estimated “ordinary” income (loss), which is our annual income (loss) from operations before tax, excluding unusual or infrequently occurring (or discrete) items. Significant management judgment is required in the projection of ordinary income (loss) in order to determine the estimated annual effective tax rate. The level of income (or loss) projected for fiscal 2015 causes an unusual relationship between income (loss) and income tax expense (benefit), with small changes resulting in: (i) a potential significant impact on the rate and, (ii) potentially unreliable estimates. As a result, we computed the provision for income taxes for the quarters and year-to-dates ended January 31, 2015 and January 31, 2014 by applying the actual effective tax rate to the year-to-date income (loss), as permitted by GAAP. The effective tax rate for the year-to-date period ended January 31, 2015 is a benefit of (28%). The principal differences in the Company's effective tax rate (benefit) for this period and the federal statutory rate of 35% are state and local income taxes net of federal benefit, the change in state rate and a valuation allowance against our deferred tax assets. No cash payments of income taxes were made during the year-to-date period ended January 31, 2015, and no significant payments are expected during the succeeding 12 months.

Alaska_Production_Credits

Alaska Production Credits	9 Months Ended
	Jan. 31, 2015
Alaska Production Credits [Abstract]
Alaska Production Credits	ALASKA PRODUCTION CREDITS
	Upon qualifying, the Company can apply for several credits under Alaska Statutes 43.55.023 and 43.55.025:
	•	43.55.023(a)(1) Qualified capital expenditure credit (20%)
	•	43.55.023(l)(1) Well lease expenditure credit (effective June 30, 2010) (40%)
	•	43.55.023(a)(2) Qualified capital exploration expenditure credit (20%)
	•	43.55.023(l)(2) Well lease exploration expenditure credit (effective June 30, 2010) (40%)
	•	43.55.023(b) Carried-forward annual loss credit (25%)
	•	43.55.025 Seismic exploration credits (40%)
	The Company recognizes a receivable when the amount of the credit is reasonably estimable and receipt is probable. For expenditure and exploration based credits, which Miller receives in the ordinary course of business, the credit is recorded as a reduction to the related assets. For carried-forward annual loss credits, which Miller receives in the ordinary course of business, the credit is recorded as a reduction to the Alaska production tax. The Company did not incur any Alaska production taxes in fiscal 2014, 2013 or 2012, and accordingly, the carried-forward annual loss credits are presented separately in its operating expenses on the condensed consolidated statements of operations.
	Balance, April 30, 2014	$	49,121
	Alaska carried-forward annual loss credits, net 1	24,240
	Applications for expenditure and exploration based credits 1	45,979
	Cash collections for expenditure and exploration based credits	(56,012		)
	Balance, January 31, 2015	$	63,328
	———————————
	1	Applications for carried-forward annual loss credits and for expenditure and exploration based credits are recorded net of established reserves and also include revisions to prior period applications, if applicable.
	During the nine months ended January 31, 2015, the Company recorded net carried-forward annual loss credits of $24,240. The Company has reduced the basis of capitalized assets by a cumulative total of $80,297 for expenditure and exploration credits. The reductions are recorded on Miller's condensed consolidated balance sheets in oil and gas properties and equipment. As of January 31, 2015 and April 30, 2014, the Company had outstanding net receivables from the State of Alaska in the amount of $63,328 and $49,121, respectively.

Litigation

Litigation	9 Months Ended
	Jan. 31, 2015
Loss Contingency, Information about Litigation Matters [Abstract]
Litigation	LITIGATION
	On May 17, 2011, we were served with a lawsuit filed in the United States District Court for the Eastern District of Tennessee at Knoxville by Troy D. Stafford, the former Chief Financial Officer of CIE.  The suit, styled Troy D. Stafford v. Miller Petroleum, Inc., Civil Action No. 3-11CV-206, claims that we terminated Mr. Stafford's employment without cause in contravention of the terms of the Purchase and Sale Agreement between us and the sellers of CIE ("PSA"), failed or refused to pay his salary, severance, percentage of purchase price, expenses or stock warrants and violated a duty of good faith and fair dealing. The suit sought damages in excess of $3,000, which includes $2,687 of damages for loss of vested warrants. We believe that all of the asserted claims were baseless, particularly in view of the fact that we issued the warrants in accordance with the terms of the PSA.  We believe that we had appropriate cause to dismiss Mr. Stafford's employment after discovering that he had breached certain representations and warranties in the PSA, and had acted in violation of our Code of Conduct. We filed our Answer and conducted discovery. On January 21, 2013, Mr. Stafford's attorney filed a motion to withdraw as counsel, and on April 2, 2013, Mr. Stafford filed a motion to proceed pro se. On February 24, 2014, we filed a Motion to Dismiss with Prejudice based on Plaintiff's failure to prosecute his case since April 2, 2013, Plaintiff's having missed filing deadlines, and his having failed to appear to give his deposition both times we have noticed it. On February 26, 2014, the Court entered an Order to Show Cause, requiring the plaintiff to demonstrate why his case should not be dismissed. On March 14, 2014, the plaintiff filed a Motion for Voluntary Dismissal, Without Prejudice through his new attorney. On June 3, 2014, the court granted plaintiff's motion to dismiss without prejudice, but did so with the condition that plaintiff must reimburse us for costs incurred by us as a result of his failure to cooperate in discovery in this case in the amount of $9 prior to his being allowed to refile the case. As such, this case has been dismissed and there is no further action currently required.
	On June 15, 2011, a breach of contract lawsuit was filed against us and CIE in the United States District Court for the Eastern District of Pennsylvania styled VAI, Inc. v. Miller Energy Resources, Inc., f/k/a Miller Petroleum, Inc. and Cook Inlet Energy, LLC. The Plaintiff alleges three causes of action: (1) breach of contract, (2) unjust enrichment, and (3) breach of the implied covenant of good faith and fair dealing. The case seeks damages in warrants to purchase our common stock and monetary damages for certain fees and expenses. The Sale Agreement with David Hall, Walter "JR" Wilcox, and Troy Stafford dated December 10, 2009 contains indemnification provisions relevant to this claim. We filed a Motion to Dismiss for lack of personal jurisdiction, but this motion was not granted by the court. We filed an Answer to the complaint in this case on October 10, 2012, and we have conducted discovery. Trial was previously set for November 4, 2013. On October 21, 2013, the trial was postponed with no new trial date having been set. On October 31, 2013, the judge ruled on our outstanding Motion for Summary Judgment, granting it as to the unjust enrichment claim and breach of the implied covenant of good faith and fair dealing claim, and denying it as to the breach of contract claim. In February 2014, we received notice from a third party seeking to intervene in the case in order to secure payment of a debt allegedly owed by the Plaintiff to the third party. On May 29, 2014, the court put down a new scheduling order setting forth certain pre-trial deadlines with the final pre-trial conference being set for October 30, 2014. On June 5, 2014, the court entered an order denying the motion to intervene. A bench trial was held January 20, 2015 through January 22, 2015. We received the verdict, dated March 9, 2015, ruling in favor of the Plaintiff and awarding it $5,463, plus interest. We believe we have grounds to move for a new trial as well as grounds to appeal this decision and are evaluating both options. We expect to file a motion requesting a new trial or a notice of appeal in the next few weeks. Given the current stage of the proceedings in this case, we currently cannot assess the probability of losses, or reasonably estimate the range of losses, related to this matter.
	In August 2011, several purported class action lawsuits were filed against us in the United States District Court for the Eastern District of Tennessee.  The lawsuits made similar claims and have been consolidated into one case, styled In re Miller Energy Resources, Inc. Securities Litigation. The suit names us, along with several of our current and former executive officers, Scott Boruff, Paul Boyd, Ford Graham, David Hall, David Voyticky, and Deloy Miller, as defendants. The Plaintiffs allege two causes of action against the defendants: (1) violation of Section 10(b) and Rule 10b-5 of the Exchange Act, (2) violation of Section 20(a) of the Exchange Act.  The case seeks money damages against us and the other defendants, and payment of the Plaintiffs' attorney's fees. We have filed a Motion to Dismiss the case, which was denied on February 4, 2014 as to all defendants save Ford Graham. On July 3, 2014, we agreed upon a settlement with the Plaintiffs under which the Plaintiffs agreed to dismiss the lawsuit with prejudice in exchange for a settlement payment of $2,950, which was within the remaining policy limits of our director and officer insurance policy. The final settlement was approved by the court, and the case was dismissed with prejudice, as of February 3, 2015, subsequent to the end of the Company's third fiscal quarter.
	On August 23, 2011, a derivative action was filed against us in Knox County Chancery Court.  The case is styled Marco Valdez, derivatively on behalf Miller Energy Resources, Inc. v. Deloy Miller, Scott M. Boruff, Jonathan S. Gross, Herman Gettelfinger, David Hall, Merrill A. McPeak, Charles M. Stivers, Don A. Turkleson, and David J. Voyticky, and Miller Energy Resources, Inc., nominal defendant.  The suit alleged the following causes of action: (1) Breach of Fiduciary Duty for disseminating false and misleading information; (2) Breach of Fiduciary Duty for failure to maintain internal controls; (3) Breach of Fiduciary Duty for failing to properly oversee and manage the company; (4) Unjust Enrichment; (5) Abuse of Control; Gross Mismanagement, and; (6) Waste of Corporate Assets.  The Plaintiff sought unspecified money damages from the individual defendants, that we take certain actions with respect to our management, restitution to us, and the Plaintiff's attorney fees and costs. The Plaintiff agreed to stay this case awaiting a ruling on the plaintiff's appeal in the federal derivatives case in Lukas v. Miller Energy Resources, Inc., et al, which, as disclosed in the Company's prior periodic reports, was ultimately dismissed in our 2014 fiscal year. The Plaintiff had agreed to voluntarily dismiss the Valdez case in the event the plaintiff's appeal in Lukas was denied. Following the dismissal of Lukas, on October 1, 2013, the Court entered an Order dismissing the Valdez case without prejudice on the motion of the Plaintiff. On October 24, 2013, we filed a Motion to Amend the Order of Dismissal as the agreement with the Plaintiff was that the case would be dismissed with prejudice if the Sixth Circuit Court of Appeals affirmed the dismissal of the Lukas case, which it did. On June 3, 2014, after reaching an agreement with the Plaintiff, we filed an amended agreed final order of dismissal with prejudice in this case. This case has been dismissed and there is no further action required.
	On August 31, 2012, we terminated an agreement with Voorhees Equipment and Consulting, Inc. ("Voorhees") for the construction and sale of the rig currently being used on the Osprey Platform, Rig 35, (the "Rig 35 Agreement"). We terminated the agreement based on our belief that Voorhees was in breach of its obligations thereunder.  Voorhees later indicated its desire to arbitrate claims it believed it had under invoices arising between May 29, 2012 and August 31, 2012.  We believed we had grounds to dispute liability with respect to some or all of those invoices, in addition to having certain counterclaims we expected to assert.  The parties elected to engage a private arbitrator to settle this dispute (the "Voorhees Matter") and conducted discovery.  On September 18, 2013, we received a third-party complaint from Voorhees in connection with a lawsuit by Carlile Transportation Systems, Inc., in the Superior Court for the State of Alaska. The case is styled Carlile Transportation Systems, Inc. v. Voorhees Rig International, Inc. v. Cook Inlet Energy, LLC (the "Carlile Matter"). The dispute in the Carlile Matter related solely to unpaid transportation fees arising from the transportation of equipment for Rig 35. These fees were already the subject of the planned arbitration with Voorhees over the Voorhees Matter. As all disputes under the Rig 35 Agreement are subject to mandatory arbitration, we filed a motion to compel arbitration in the Carlile Matter, which the Court granted, along with an award of our legal costs incurred in connection with the Carlile Matter. On February 20, 2014, we reached an agreement in principle to settle the Voorhees Matter (including the transportation fees at issue in the Carlile Matter), and we entered into a settlement agreement which was effective as of May 12, 2014. We agreed to return to Voorhees the following equipment previously delivered to us under the Rig 35 Agreement, but which we subsequently replaced on that rig:
	•	an iron roughneck that we had to replace on Rig 35 due to mechanical unreliability; and
	•	a BOP stack originally included on Rig 35, but later removed and replaced with a better functioning replacement.
	We also agreed to return, and have since returned, to Voorhees two moving containers, left-over electrical equipment and tools belonging to Voorhees but left with CIE when Voorhees ceased working on Rig 35. No costs of defense or other cash payment were required of us in connection with this settlement, although we did pay the transportation costs of the equipment being returned. As a result, we recorded a gain of $113 related to this settlement in other income (expense), net in our condensed consolidated statement of operations for the nine months ended January 31, 2015. As this matter has been resolved, no further action is required.
	On April 4, 2013, we filed suit against a former contractor of CIE and its parent company (collectively "Cudd") in the United States District Court for the District of Alaska at Anchorage. This case is styled Cook Inlet Energy, LLC v. Cudd Pressure Control Inc. and RPC, Inc. In our suit we are seeking declaratory relief and damages for breach of contract, breach of the implied warranty of merchantability, breach of the implied covenant of fitness for a particular purpose and breach of the implied covenant of good faith and fair dealing arising out of a dispute regarding certain equipment and services provided by Cudd on the Osprey Platform that did not meet our needs or expectations as promised. We have not yet determined the full amount of damages claimed. On May 29, 2013, Cudd filed its answer denying our claims and including a counterclaim for equipment and services, totaling approximately $1,889 plus the costs of defense. We have filed our counteranswer and denied that these amounts are owed, in whole or in part. We are presently conducting discovery. A mediation was held on February 24, 2015, subsequent to the end of our third fiscal quarter. Given the current stage of the proceedings with respect to this case, we believe that any loss would be limited to $1,889 plus the cost of defense, related to this matter. Based on the information currently available, we have accrued our best estimate of the potential loss on our condensed consolidated balance sheet.
	On February 7, 2014, we were served with a lawsuit filed by Vulcan Capital Corporation ("Vulcan") in the District Court for the Southern District of New York styled Vulcan Capital Corp. v. Miller Energy Resources, Inc. and PlainsCapital Bank. The suit asserts various causes of action against PlainsCapital Bank, and appears to assert the following causes of action against us: (1) Breach of Fiduciary Duty and (2) Concert of Action. The case stems from an agreement Vulcan had with PlainsCapital Bank wherein Vulcan secured certain loans by pledging four warrants to purchase our common stock that were issued as part of the employment package of Ford F. Graham, our former President. Upon Vulcan's default of the loan agreement, PlainsCapital Bank presented the warrants to us for transfer, and, after requesting certain tenders required under Tennessee law, we registered the transfer of the warrants. Pursuant to a motion from Plains Capital Bank, the case was transferred to Texas. We filed a motion to dismiss the case against the Company on October 9, 2014, which was granted on January 22, 2015. The court did, however, give Vulcan 30 days to replead their concert of action/civil conspiracy claim. An amended complaint as to this cause of action was filed on February 23, 2015. We are currently drafting a responsive pleading. In addition, we note that PlainsCapital Bank has agreed to indemnify us for our first $500 of expenses related to this dispute. Given the current state of the proceedings in this case, we currently cannot assess the probability of losses, or reasonably estimate the range of losses, related to this matter.
	We are also party to various routine legal proceedings arising in the ordinary course of our business. Management believes that none of these actions, individually or in the aggregate, will have a material adverse effect on our financial condition or results of operations.

Subsequent_Events

Subsequent Events	9 Months Ended
	Jan. 31, 2015
Subsequent Events [Abstract]
Subsequent Events	SUBSEQUENT EVENTS
	Payment of Dividends
	The following table summarizes the Series B Preferred Stock, Series C Preferred Stock and Series D Preferred Stock dividend activity subsequent to January 31, 2015.
	Series	Declaration Date	Dividend Paid per Share		Annualized Percentage Rate		Par Value		Accrual Period	Record Date	Payment Date
	B	30-Jan-15	$	5.95	12	%	$	100	Sept. 1, 2014 - Feb. 28, 2015	13-Feb-15	2-Mar-15
	C	30-Jan-15	$	0.67	10.75	%	$	25	Dec. 1, 2014 - Feb. 28, 2015	13-Feb-15	2-Mar-15
	D	30-Jan-15	$	0.66	10.5	%	$	25	Dec. 1, 2014 - Feb. 28, 2015	13-Feb-15	2-Mar-15
	First Lien RBL Amendment
	On March 11, 2015, the Company entered into a Waiver and Fourth Amendment to Credit Agreement and Second Amendment to Guarantee and Collateral Agreement (the "March 2015 First Lien Amendment") to the First Lien RBL. The March 2015 First Lien Amendment, among other things, (i) allows us 60 days from the date of the March 2015 First Lien Amendment to provide a mortgage to the RBL Lenders covering the North Fork Pipeline and 30 days from that date to have Savant deliver a mortgage in favor of the RBL Lenders covering its oil and gas properties, (ii) adds a requirement that we engage a field auditor and complete a review of our accounts payable, (iii) requires that we deliver to the RBL Administrative Agent an engineering report on or before May 1, 2015 which will serve as the basis of an interim redetermination of the borrowing base under the First Lien Loan Agreement, which will be permitted in addition to the other redeterminations otherwise permitted under the First Lien Loan Agreement, (iv) sets new minimum liquidity requirements, (v) amends APOD A and certain defined terms, (vi) requires that we apply certain expected tax credit receipts to pay down the outstanding balance of the loans outstanding under the First Lien Loan Agreement, (vii) amends restrictions on minimum availability that must be maintained under the First Lien Loan Agreement, includes additional restrictions on capital expenditures, (viii) permits us to issue an additional $50,000 in preferred stock, measured in terms of the stated liquidation preference of that stock (to a total of $100,000 and requires that we raise at least $10,000 of net cash proceeds from the issuance of preferred equity interests on or before April 30, 2015, (ix) amends the borrowing base to $45,000 for the period beginning on the date of the March 2015 First Lien Amendment until the next redetermination date, (x) amends and updates a list of pledged equity interests attached as Schedule 2 to the associated Guarantee and Collateral Agreement in favor of the RBL Lenders, (xi) by an amendment to the definition of "Applicable Margin," increases the interest rates payable on the loans outstanding under the First Lien RBL by 1.0%, as compared to the interest rates payable prior to the date of the March 2015 First Lien Amendment, and (xii) provides waivers related to certain events of default resulting from (A) the impairment of our proved reserves, (B) our issuance of preferred equity interests with a stated liquidation preference in excess of $50,000, (C) the existence of debt in the form of accounts payable that were greater than 90 days past due, (D) our failure to provide an executed mortgage and related legal opinions on the North Fork Pipeline when due pursuant to a prior amendment, (E) our payment of dividends on our preferred stock while an event of default existed under the First Lien Loan Agreement, and (F) related cross defaults arising under the Second Lien Credit Facility.
	Second Lien Amendment
	On March 11, 2015, the Company entered into a Waiver and Amendment No. 5 to Credit Agreement and Amendment No. 3 to Guarantee and Collateral Agreement (the "March 2015 Second Lien Amendment") to the Second Lien Credit Agreement. The March 2015 Second Lien Amendment, among other things, (i) allows us 60 days from the date of the 2015 Second Lien Amendment to provide a mortgage to the Second Lien Lenders covering the North Fork Pipeline and 30 days from that date to have Savant deliver a mortgage in favor of the Second Lien Lenders covering its oil and gas properties, (ii) adds a requirement that we engage a field auditor and complete a review of our accounts payable, (iii) requires that we deliver to the Second Lien Agent an engineering report on or before May 1, 2015, (iv) amends the provision on “additional interest” to require that we pay an additional 1.0% interest in cash plus 2.0% interest in kind on the loans outstanding under the Second Lien Credit Agreement (subject to future reductions of the additional interest payable in kind if certain operational and capital expenditure conditions are met by May 31, 2015), (v) amends APOD A and certain defined terms, (vi) includes additional restrictions on capital expenditures, (vii) permits us to issue an additional $50,000 in preferred stock, measured in terms of the stated liquidation preference of that stock (to a total of $100,000 in stated liquidation preference) and requires that we raise at least $10,000 of net cash proceeds from the issuance of preferred equity interests on or before April 30, 2015, (viii) amends and updates a list of pledged equity interests attached as Schedule 2 to the associated Guarantee and Collateral Agreement in favor of the Second Lien Lenders, and (ix) provides waivers related to certain events of default resulting from (A) the impairment of our proved reserves, (B) our issuance of preferred equity interests with a stated liquidation preference in excess of $50,000, (C) the existence of debt in the form of accounts payable that are greater than 90 days past due, (D) our failure to provide an executed mortgage and related legal opinions on the North Fork Pipeline pursuant to a prior amendment, (E) our payment of dividends on our preferred stock while an Event of Default existed, and (F) related cross defaults arising under the First Lien Credit Facility.
	Verdict in VAI, Inc. v Miller Energy Resources Litigation
	As describe more fully in Note 15 - Litigation, on June 15, 2011, a breach of contract lawsuit was filed against us and CIE in the United States District Court for the Eastern District of Pennsylvania styled VAI, Inc. v. Miller Energy Resources, Inc., f/k/a Miller Petroleum, Inc. and Cook Inlet Energy, LLC. Following a bench trial, we received a verdict in this case, dated March 9, 2015, ruling in favor of the Plaintiff and awarding it $5,463, plus interest. We believe we have grounds to move for a new trial as well as grounds to appeal this decision and are evaluating both options. We expect to file a motion requesting a new trial or a notice of appeal in the next few weeks. Given the current stage of the proceedings in this case, we currently cannot assess the probability of losses, or reasonably estimate the range of losses, related to this matter.

Organization_and_Basis_of_Pres1

Organization and Basis of Presentation (Policies)	9 Months Ended
	Jan. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation
	The accompanying condensed consolidated financial statements are presented in accordance with GAAP and, in the opinion of management, include all adjustments (consisting only of normal recurring adjustments) necessary for a fair statement of the results for the interim periods. Certain information and note disclosures normally included in annual financial statements prepared in accordance with GAAP have been condensed or omitted under Securities and Exchange Commission ("SEC") rules and regulations. The results reported in these condensed consolidated financial statements are not necessarily indicative of the financial position or operating results that may be expected for the entire year.
	The financial information included herein should be read in conjunction with the audited consolidated financial statements and notes thereto included in Item 8 of Part II of the Company's Annual Report on Form 10-K for the year ended April 30, 2014, which was filed with the SEC on July 14, 2014, and amended on July 15, 2014.
	Certain amounts in prior fiscal years have been reclassified to conform with the presentation adopted in the current year.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Jan. 31, 2015
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation
	The accompanying condensed consolidated financial statements include the Company's consolidated accounts after elimination of intercompany balances and transactions. The condensed consolidated financial statements also include the accounts of all investments in which Miller, either through direct or indirect ownership, has more than a 50% interest or significant influence over the management of those entities.
Use of Estimates	Use of Estimates
	The preparation of financial statements requires us to utilize estimates and make judgments that affect the reported amounts of assets, liabilities, revenues and expenses and related disclosure of contingent assets and liabilities. These estimates are based on historical experience and on various other assumptions that we believe to be reasonable under the circumstances. The estimates are evaluated by management on an ongoing basis and the results of these evaluations form a basis for making decisions about the carrying value of assets and liabilities that are not readily apparent from other sources. Although actual results may differ from these estimates under different assumptions or conditions, we believe that the estimates used in the preparation of our financial statements are reasonable.
Oil and Gas Properties	Oil and Gas Properties
	The Company follows the successful efforts method of accounting for oil and gas properties. Under this method, exploration costs, such as exploratory geological and geophysical costs, delay rentals and exploration overhead, are charged against earnings as incurred. Acquisition costs and costs of drilling exploratory wells are capitalized pending determination of whether proved reserves can be attributed to the area as a result of drilling the well. If management determines that commercial quantities of hydrocarbons have not been discovered, capitalized costs associated with exploratory wells are charged to exploration expense.
	Costs of drilling and equipping successful wells, costs to construct or acquire facilities, and associated asset retirement costs are depleted using the unit-of-production method based on total estimated proved developed reserves. Costs of acquiring proved properties, including leasehold acquisition costs transferred from unproved properties and costs to construct or acquire offshore platforms, and associated asset retirement costs are depleted using the unit-of-production method based on total estimated proved reserves.
	When circumstances indicate that proved properties may be impaired, the Company compares expected undiscounted future net cash flows, calculated using the Company's estimate of future oil and natural gas prices, operating expenses and production, to the net book value of the proved properties on a field by field basis. If the sum of the expected undiscounted future net cash flows is less than the net book value of the proved properties, an impairment loss is recognized for the excess, if any, of the net book value over its estimated fair value. See Note 6 for a discussion of asset impairments.
	Acquisition costs of unproved properties are assessed for impairment during the holding period and transferred to proved oil and gas properties to the extent the costs are associated with successful exploration activities. Significant undeveloped leases are assessed individually for impairment based on our current exploration plans, and a valuation allowance is provided if impairment is indicated. Costs of expired or abandoned leases are charged to expense, while costs of productive leases are transferred to proved oil and gas properties. Costs of maintaining and retaining unproved properties are included in oil and gas operating expense and impairments of unsuccessful leases are included in exploration expense.
Loss Per Share	Loss Per Share
	The Company determines basic income (loss) per share and diluted income (loss) per share in accordance with the provisions of ASC 260, "Earnings Per Share." Basic income (loss) per share excludes dilution and is computed by dividing earnings available to common stockholders by the weighted-average number of common shares outstanding for the period. The calculation of diluted earnings (loss) per share is similar to that of basic earnings per share, except that the denominator is increased, if net income is positive, to include the number of additional common shares that would have been outstanding if all potentially dilutive common shares, such as those issuable upon the exercise of stock options and warrants, had been exercised. The Company computes the numerator for basic income (loss) by subtracting accretion of preferred stock and cumulative preferred stock dividends from net income (loss) to arrive at net income (loss) attributable to common stockholders. Preferred stock dividends include dividends declared on preferred stock (regardless of whether the dividends have been paid) and dividends accumulated for the period on cumulative preferred stock (regardless of whether the dividends have been declared). As of January 31, 2015, our cumulative preferred dividends were $10,775.
Deferred Escalating Minimum Rent	Deferred Escalating Minimum Rent
	Certain of Miller's operating leases contain predetermined fixed escalations of the minimum rentals during the term of the lease, which includes option periods where failure to exercise such options would result in an economic penalty. For these leases, the Company recognizes the related rental expense on a straight-line basis over the life of the lease, beginning with the point at which Miller obtains control and possession of the leased properties, and records the difference between the amounts charged to operations and amounts paid as deferred escalating minimum rent. Any lease incentives received are deferred and subsequently amortized on a straight-line basis over the life of the lease as a reduction to rent expense.
New Accounting Pronouncements Issued	New Accounting Pronouncements Issued But Not Yet Adopted
	In May 2014, the FASB issued ASU 2014-09, "Revenue from Contracts with Customers (Topic 606)." ASU 2014-09 is intended to improve the financial reporting requirements for revenue from contracts with customers by providing a principle based approach. The core principle of the standard is that revenue should be recognized when the transfer of promised goods or services is made in an amount that the entity expects to be entitled to in exchange for the transfer of goods and services. ASU 2014-09 also requires disclosures enabling users of financial statements to understand the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers. This standard will be effective for financial statements issued by public companies for annual reporting periods beginning after December 15, 2016. Early adoption is not permitted. The Company is currently evaluating the potential impact of ASU 2014-09 on the consolidated financial statements.
	In August 2014, the FASB issued ASU 2014-15, "Presentation of Financial Statements - Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity's Ability to Continue as a Going Concern" which describes how an entity's management should assess whether there are conditions and events that raise substantial doubt about an entity's ability to continue as a going concern within one year after the date that the financial statements are issued. Management should consider both quantitative and qualitative factors in making its assessment. The new standard applies to all entities for the first annual period ending after December 15, 2016, and for annual and interim periods thereafter. Early application is permitted. The Company will assess the potential impact of ASU 2014-15 when applicable circumstances are present.
	In November 2014, the FASB issued ASU 2014-16, "Derivatives and Hedging (Topic 815): Determining Whether the Host Contract in a Hybrid Financial Instrument Issued in the Form of a Share is More Akin to Debt or to Equity." ASU 2014-16 clarifies how current U.S. GAAP should be interpreted in evaluating the economic characteristics and risk of a host contract in a hybrid financial instrument that is issued in the form of a share. In addition, ASU 2014-16 was issued to clarify that in evaluating the nature of a host contract, an entity should assess the substance of the relevant terms and features, such as the relative strength of the debt-like or equity-like terms and features given the facts and circumstances, when considering how to weight those terms and features. The effects of initially adopting ASU 2014-16 should be applied on a modified retrospective basis to existing hybrid financial instruments issued in a form of a share as of the beginning of the fiscal year for which the amendments are effective. Retrospective application is permitted to all relevant prior periods. ASU 2014-16 is effective fiscal years, and interim periods within those fiscal years, beginning after December 15, 2015. Early adoption in an interim period is permitted. The Company will continue to determine the effects, if any, of ASU 2014-16 on its consolidated financial statements.
	New Accounting Pronouncements Issued and Adopted
	In April 2014, the FASB issued ASU 2014-08, "Presentation of Financial Statements (Topic 205) and Property, Plant, and Equipment (Topic 360): Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity." ASU 2014-08 changes the definition of a discontinued operation to include only those disposals of components of an entity representative of a strategic shift which has (or will have) a major effect on an entity's operations and financial results. In addition, ASU 2014-08 requires additional disclosures about both discontinued operations and the disposal of an individually significant component of an entity that does not qualify for discontinued operations presentation in the financial statements. The guidance is effective prospectively for fiscal years, and interim periods within those years, beginning after December 15, 2014, with early adoption permitted. We adopted the provisions of ASU 2014-08 on a prospective basis during the first quarter of fiscal year 2015. The adoption of this ASU did not have an impact on the Company's condensed consolidated financial statements.
	There are no other recently issued accounting pronouncements that are expected to have a material impact on the Company's financial condition, results of operations or cash flows.

Acquisitions_and_Divestitures_

Acquisitions and Divestitures (Tables)	9 Months Ended
	Jan. 31, 2015
Savant Alaska, LLC [Member]
Business Acquisition [Line Items]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	The following table summarizes the consideration paid for Savant and the allocation of the purchase price to the assets acquired and liabilities assumed which have been included in the Company's condensed consolidated financial statements. The Company is in the process of finalizing the evaluation of the assigned fair values to the assets acquired and liabilities assumed.
		Purchase Price Allocation
	Cash Consideration Paid and Promissory Notes Issued for the Acquisition:
	Cash paid	$	6,000
	Promissory notes	3,000
	Consideration paid	$	9,000
	Preliminary Allocation of Assets Acquired and Liabilities Assumed:
	Current assets	$	9,772
	Proved oil and gas properties	1,840
	Crude oil pipeline	585
	Support equipment	592
	Other assets	408
	Current liabilities	(2,757		)
	Asset retirement obligation	(1,440		)
	Fair value of assets acquired and liabilities assumed	$	9,000
Business Acquisition, Pro Forma Information	The pro forma information is not necessarily indicative of the results of operations as it would have been had these transactions been effected on the assumed date:
		Three Months Ended January 31,						Nine Months Ended January 31,
		2015			2014			2015			2014
	Revenues	$	21,737		$	22,747		$	83,322		$	67,892
	Net loss attributable to common shareholders	$	(159,430	)	$	(5,219	)	$	(344,158	)	$	(16,622	)
	Net loss per common share, basic and diluted	$	(3.42	)	$	(0.12	)	$	(7.43	)	$	(0.38	)
Anchor Point Pipeline [Member]
Business Acquisition [Line Items]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	The following table summarizes the consideration paid for the Anchor Point Pipeline and the allocation of the purchase price to the assets acquired and liabilities assumed which have been included in the Company's condensed consolidated financial statements. The Company is in the process of finalizing the evaluation of the assigned fair values to the assets acquired and liabilities assumed.
		Purchase Price Allocation
	Consideration Issued for Acquisition:
	Series D Preferred Stock	$	5,446
	Preliminary Allocation of Assets Acquired and Liabilities Assumed:
	Natural gas pipeline and pipeline support equipment	$	5,687
	Asset retirement obligation	(241		)
	Fair value of assets acquired and liabilities assumed	$	5,446

Oil_and_Gas_Properties_and_Equ1

Oil and Gas Properties and Equipment (Tables)	9 Months Ended
	Jan. 31, 2015
Property, Plant and Equipment [Line Items]
Depreciation, Depletion, and Amortization	Depreciation, depletion and amortization consisted of the following:
		For the Nine Months Ended January 31,
		2015			2014
	Depletion of oil and gas related assets	$	53,240		$	19,158
	Depreciation and amortization of equipment	3,361			3,194
	Total	$	56,601		$	22,352
Oil and Gas Properties [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment	Oil and gas properties (successful efforts method) are summarized as follows:
		January 31,			April 30,
		2015			2014
	Property costs:
	Proved property	$	476,694		$	467,740
	Unproved property	47,984			243,230
	Total property costs	524,678			710,970
	Less: Accumulated depletion	(334,956		)	(66,143		)
	Oil and gas properties, net	$	189,722		$	644,827
Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment	Equipment is summarized as follows:
		January 31,			April 30,
		2015			2014
	Machinery and equipment	$	2,821		$	7,759
	Vehicles	1,425			1,877
	Buildings	2,043			2,726
	Office equipment	1,054			1,108
	Leasehold improvements	676			527
	Drilling rigs	44,581			30,210
	Capital lease asset	4,022			1,500
	Pipeline and pipeline support assets	6,255			—
		62,877			45,707
	Less: Accumulated depreciation	(11,186		)	(10,338		)
	Equipment, net	$	51,691		$	35,369

Derivative_Instruments_Tables

Derivative Instruments (Tables)	9 Months Ended
	Jan. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Derivative Instruments	As of January 31, 2015, the Company had the following open crude oil derivative positions. All are priced based on the Brent crude oil futures as traded on the Intercontinental Exchange.
			Fixed - Price Swaps
	Production Period ending April 30,		Bbls			Weighted Average Fixed Price
	2015		191,400			$	97.09
	2016		787,600			$	95.36
	2017		232,600			$	93.97
Schedule of Derivative Liabilities at Fair Value	The following table presents the fair value of commodity derivatives. The fair value amounts are presented on a gross basis and do not reflect the netting of asset and liability positions permitted under the terms of Miller's master netting arrangements.
			Asset Derivatives											Liability Derivatives
			January 31, 2015						April 30, 2014					January 31, 2015				April 30, 2014
	Derivatives not designated as hedging instruments under ASC 815		Balance Sheet Location		Fair Value				Balance Sheet Location		Fair Value			Balance Sheet Location		Fair Value		Balance Sheet Location	Fair Value
	Commodity derivatives		Short-term portion of derivative instruments		$	29,513			Short-term portion of derivative instruments		$	88		Short-term portion of derivative instruments		$	—	Short-term portion of derivative instruments	$	(3,315	)
	Commodity derivatives		Long-term portion of derivative instruments		12,027				Long-term portion of derivative instruments		26			Long-term portion of derivative instruments		—		Long-term portion of derivative instruments	(4,006		)
	Total derivatives not designated as hedging instruments under ASC 815				$	41,540					$	114				$	—		$	(7,321	)
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value	The following table presents the Company's gross and net derivative assets and liabilities:
		Gross Amount Presented on Balance Sheet				Netting Adjustments (a)				Net Amount
	January 31, 2015
	Derivative assets with right of offset or master netting agreements	$	41,540			$	—			$	41,540
	April 30, 2014
	Derivative assets with right of offset or master netting agreements	$	114			$	(114	)		$	—
	Derivative liabilities with right of offset or master netting agreements	$	(7,321	)		$	114			$	(7,207	)
	—————————
	(a)	The Company has an agreement in place that allows for the financial right of offset for derivative assets and derivative liabilities at settlement or in the event of default under the agreement.
Schedule of Derivative Instruments, Gain (Loss) in Statement of Financial Performance	Gains and losses on derivatives are reported in the condensed consolidated statements of operations. The following represents the Company's reported gains and losses on derivative instruments for the periods presented:
		For the Three Months Ended January 31,								For the Nine Months Ended January 31,
		2015				2014				2015			2014
	Gain (loss) on derivatives, net	$	39,330			$	1,677			$	55,516		$	(5,589	)

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	9 Months Ended
	Jan. 31, 2015
Fair Value Disclosures [Abstract]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	The following summarizes the fair value of the Company's commodity derivative assets and liabilities according to their fair value hierarchy as of the reporting dates indicated:
		Fair Value Measurements
	At January 31, 2015	Level 1		Level 2			Level 3
	Commodity derivative asset	$	—	$	41,540		$	—
	Commodity derivative liability	—		—			—
	Total	$	—	$	41,540		$	—
	At April 30, 2014
	Commodity derivative asset	$	—	$	114		$	—
	Commodity derivative liability	—		(7,321		)	—
	Total	$	—	$	(7,207	)	$	—

Debt_Tables

Debt (Tables)	9 Months Ended
	Jan. 31, 2015
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments	As of January 31, 2015 and April 30, 2014, the Company had the following debt obligations:
		January 31,				April 30,
		2015				2014
	Second Lien Credit Facility	$	175,000			$	175,000
	Debt discount related to Second Lien Credit Facility	(2,639		)		(3,296		)
	First Lien RBL	44,000				—
	Savant Promissory Notes payable	2,000				—
	Gunsight Promissory Note payable	—				950
	Apollo prepayment and extension fee note payable	2,306				9,223
	Capital lease obligation	2,756				—
	Series B Preferred Stock	2,382				2,325
	Total debt obligations	225,805				184,202
	Less: Current maturities	(29,553		)		(9,459		)
	Total debt less current maturities	$	196,252			$	174,743
Schedule of Line of Credit Facilities Borrowing Base Utilization	Amounts outstanding under the First Lien RBL are priced on a sliding scale, based on LIBOR plus 300 to 400 basis points, depending upon the level of borrowing (per the table below).
	Borrowing Base Utilization Grid
	Borrowing base utilization percentage	<25%	≥ 25%, but <50%	≥ 50%, but <75%	≥ 75%, but <90%	≥ 90%, but ≤100%
	Spread above LIBOR	3.00%	3.25%	3.50%	3.75%	4.00%
	Undrawn commitment fee rate	0.50%	0.50%	0.75%	0.75%	0.75%
Dividends Declared	The following table summarizes the Series B Preferred Stock dividend activity for the nine months ended January 31, 2015.
	Series		Declaration Date		Dividend per Share				Annualized Percentage Rate		Par Value		Accrual Period	Record Date	Payment Date
	B		July 28, 2014		$	6.05			12	%	$	100	Mar. 1 - Aug. 31, 2014	August 15, 2014	September 2, 2014
	B		January 30, 2015		$	5.95			12	%	$	100	Sept. 1, 2014 - Feb. 28, 2015	February 13, 2015	March 2, 2015
	The following table summarizes the Series C Preferred Stock and Series D Preferred Stock dividend activity for the nine months ended January 31, 2015.
	Series		Declaration Date		Dividend per Share				Annualized Percentage Rate		Par Value		Accrual Period	Record Date	Payment Date
	C		July 28, 2014		$	0.67			10.75	%	$	25	Jun. 1 - Aug. 31, 2014	August 15, 2014	September 2, 2014
	D		July 28, 2014		$	0.66			10.5	%	$	25	Jun. 1 - Aug. 31, 2014	August 15, 2014	September 2, 2014
	C		October 29, 2014		$	0.67			10.75	%	$	25	Sept. 1 - Nov. 30, 2014	November 14, 2014	December 1, 2014
	D		October 29, 2014		$	0.66			10.5	%	$	25	Sept. 1 - Nov. 30, 2014	November 14, 2014	December 1, 2014
	C		January 30, 2015		$	0.67			10.75	%	$	25	Dec. 1, 2014 - Feb. 28, 2015	February 13, 2015	March 2, 2015
	D		January 30, 2015		$	0.66			10.5	%	$	25	Dec. 1, 2014 - Feb. 28, 2015	February 13, 2015	March 2, 2015
	The following table summarizes the Series B Preferred Stock, Series C Preferred Stock and Series D Preferred Stock dividend activity subsequent to January 31, 2015.
	Series		Declaration Date		Dividend Paid per Share				Annualized Percentage Rate		Par Value		Accrual Period	Record Date	Payment Date
	B		30-Jan-15		$	5.95			12	%	$	100	Sept. 1, 2014 - Feb. 28, 2015	13-Feb-15	2-Mar-15
	C		30-Jan-15		$	0.67			10.75	%	$	25	Dec. 1, 2014 - Feb. 28, 2015	13-Feb-15	2-Mar-15
	D		30-Jan-15		$	0.66			10.5	%	$	25	Dec. 1, 2014 - Feb. 28, 2015	13-Feb-15	2-Mar-15

Asset_Retirement_Obligations_T

Asset Retirement Obligations (Tables)	9 Months Ended
	Jan. 31, 2015
Asset Retirement Obligation Disclosure [Abstract]
Schedule of Asset Retirement Obligations	The following table presents changes to the Company's asset retirement obligation ("ARO") liability for the nine months ended January 31, 2015 and 2014:
		2015			2014
	Asset retirement obligation, as of April 30,	$	22,872		$	19,890
	Additions	2,206			196
	Revisions	(100		)	—
	Sold wells	(1,495		)	—
	Accretion expense	1,067			903
	Settlements	(121		)	(22		)
	North Fork properties purchase price adjustment	159			—
	Asset retirement obligation, as of January 31,	$	24,588		$	20,967

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	9 Months Ended
	Jan. 31, 2015
Share-based Compensation [Abstract]
Schedule of Share-based Compensation, Activity	The following table summarizes stock options and warrants activity for the period presented:
		Number of Options and Warrants		Weighted Average Exercise Price
	Beginning balance at April 30, 2014	15,021,347		$	4.99
	Granted	2,720,500		4.53
	Exercised	(329,939	)	4.37
	Cancelled	(1,380,460	)	4.95
	Ending balance	16,031,448		4.93
	Options and warrants exercisable at January 31, 2015	13,760,634		$	4.96
Schedule of Share-based Compensation, Shares and Warrants Authorized under Stock Option Plans, by Exercise Price Rance	The following table summarizes stock options and warrants outstanding, including exercisable shares at January 31, 2015:
	Options and Warrants Outstanding							Options and Warrants
								Exercisable
	Range of Exercise Price		Number Outstanding		Weighted Average Remaining Contractual Life (in years)	Weighted Average Exercise Price		Number Exercisable	Weighted Average Exercise Price
	$0.01 to $1.24		1,361,000		1.3	$	0.63	1,311,000	$	0.61
	$2.00 to $4.99		3,673,001		7	4.04		2,227,687	3.77
	$5.15 to $5.53		4,137,447		2.2	5.32		3,641,947	5.33
	$5.68 to $5.94		3,435,000		5.8	5.9		3,195,000	5.92
	$6.00 to $6.95		3,425,000		1.9	6.13		3,385,000	6.12
			16,031,448		3.9	$	4.93	13,760,634	$	4.96
Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity	The following table summarizes restricted stock activity for the nine months ended January 31, 2015:
	Unvested at April 30, 2014	465,432
	Granted	945,655
	Vested	(1,182,587	)
	Cancelled	(28,000	)
	Unvested at January 31, 2015	200,500

Stockholders_Equity_Tables

Stockholders' Equity (Tables)	9 Months Ended
	Jan. 31, 2015
Stockholders' Equity Note [Abstract]
Dividends Declared	The following table summarizes the Series B Preferred Stock dividend activity for the nine months ended January 31, 2015.
	Series	Declaration Date	Dividend per Share		Annualized Percentage Rate		Par Value		Accrual Period	Record Date	Payment Date
	B	July 28, 2014	$	6.05	12	%	$	100	Mar. 1 - Aug. 31, 2014	August 15, 2014	September 2, 2014
	B	January 30, 2015	$	5.95	12	%	$	100	Sept. 1, 2014 - Feb. 28, 2015	February 13, 2015	March 2, 2015
	The following table summarizes the Series C Preferred Stock and Series D Preferred Stock dividend activity for the nine months ended January 31, 2015.
	Series	Declaration Date	Dividend per Share		Annualized Percentage Rate		Par Value		Accrual Period	Record Date	Payment Date
	C	July 28, 2014	$	0.67	10.75	%	$	25	Jun. 1 - Aug. 31, 2014	August 15, 2014	September 2, 2014
	D	July 28, 2014	$	0.66	10.5	%	$	25	Jun. 1 - Aug. 31, 2014	August 15, 2014	September 2, 2014
	C	October 29, 2014	$	0.67	10.75	%	$	25	Sept. 1 - Nov. 30, 2014	November 14, 2014	December 1, 2014
	D	October 29, 2014	$	0.66	10.5	%	$	25	Sept. 1 - Nov. 30, 2014	November 14, 2014	December 1, 2014
	C	January 30, 2015	$	0.67	10.75	%	$	25	Dec. 1, 2014 - Feb. 28, 2015	February 13, 2015	March 2, 2015
	D	January 30, 2015	$	0.66	10.5	%	$	25	Dec. 1, 2014 - Feb. 28, 2015	February 13, 2015	March 2, 2015
	The following table summarizes the Series B Preferred Stock, Series C Preferred Stock and Series D Preferred Stock dividend activity subsequent to January 31, 2015.
	Series	Declaration Date	Dividend Paid per Share		Annualized Percentage Rate		Par Value		Accrual Period	Record Date	Payment Date
	B	30-Jan-15	$	5.95	12	%	$	100	Sept. 1, 2014 - Feb. 28, 2015	13-Feb-15	2-Mar-15
	C	30-Jan-15	$	0.67	10.75	%	$	25	Dec. 1, 2014 - Feb. 28, 2015	13-Feb-15	2-Mar-15
	D	30-Jan-15	$	0.66	10.5	%	$	25	Dec. 1, 2014 - Feb. 28, 2015	13-Feb-15	2-Mar-15

Alaska_Production_Credits_Tabl

Alaska Production Credits (Tables)	9 Months Ended
	Jan. 31, 2015
Alaska Production Credits [Abstract]
Allowance for Credit Losses on Financing Receivables	The Company recognizes a receivable when the amount of the credit is reasonably estimable and receipt is probable. For expenditure and exploration based credits, which Miller receives in the ordinary course of business, the credit is recorded as a reduction to the related assets. For carried-forward annual loss credits, which Miller receives in the ordinary course of business, the credit is recorded as a reduction to the Alaska production tax. The Company did not incur any Alaska production taxes in fiscal 2014, 2013 or 2012, and accordingly, the carried-forward annual loss credits are presented separately in its operating expenses on the condensed consolidated statements of operations.
	Balance, April 30, 2014	$	49,121
	Alaska carried-forward annual loss credits, net 1	24,240
	Applications for expenditure and exploration based credits 1	45,979
	Cash collections for expenditure and exploration based credits	(56,012		)
	Balance, January 31, 2015	$	63,328
	———————————
	1	Applications for carried-forward annual loss credits and for expenditure and exploration based credits are recorded net of established reserves and also include revisions to prior period applications, if applicable.

Subsequent_Events_Tables

Subsequent Events (Tables)	9 Months Ended
	Jan. 31, 2015
Subsequent Events [Abstract]
Dividends Declared	The following table summarizes the Series B Preferred Stock dividend activity for the nine months ended January 31, 2015.
	Series	Declaration Date	Dividend per Share		Annualized Percentage Rate		Par Value		Accrual Period	Record Date	Payment Date
	B	July 28, 2014	$	6.05	12	%	$	100	Mar. 1 - Aug. 31, 2014	August 15, 2014	September 2, 2014
	B	January 30, 2015	$	5.95	12	%	$	100	Sept. 1, 2014 - Feb. 28, 2015	February 13, 2015	March 2, 2015
	The following table summarizes the Series C Preferred Stock and Series D Preferred Stock dividend activity for the nine months ended January 31, 2015.
	Series	Declaration Date	Dividend per Share		Annualized Percentage Rate		Par Value		Accrual Period	Record Date	Payment Date
	C	July 28, 2014	$	0.67	10.75	%	$	25	Jun. 1 - Aug. 31, 2014	August 15, 2014	September 2, 2014
	D	July 28, 2014	$	0.66	10.5	%	$	25	Jun. 1 - Aug. 31, 2014	August 15, 2014	September 2, 2014
	C	October 29, 2014	$	0.67	10.75	%	$	25	Sept. 1 - Nov. 30, 2014	November 14, 2014	December 1, 2014
	D	October 29, 2014	$	0.66	10.5	%	$	25	Sept. 1 - Nov. 30, 2014	November 14, 2014	December 1, 2014
	C	January 30, 2015	$	0.67	10.75	%	$	25	Dec. 1, 2014 - Feb. 28, 2015	February 13, 2015	March 2, 2015
	D	January 30, 2015	$	0.66	10.5	%	$	25	Dec. 1, 2014 - Feb. 28, 2015	February 13, 2015	March 2, 2015
	The following table summarizes the Series B Preferred Stock, Series C Preferred Stock and Series D Preferred Stock dividend activity subsequent to January 31, 2015.
	Series	Declaration Date	Dividend Paid per Share		Annualized Percentage Rate		Par Value		Accrual Period	Record Date	Payment Date
	B	30-Jan-15	$	5.95	12	%	$	100	Sept. 1, 2014 - Feb. 28, 2015	13-Feb-15	2-Mar-15
	C	30-Jan-15	$	0.67	10.75	%	$	25	Dec. 1, 2014 - Feb. 28, 2015	13-Feb-15	2-Mar-15
	D	30-Jan-15	$	0.66	10.5	%	$	25	Dec. 1, 2014 - Feb. 28, 2015	13-Feb-15	2-Mar-15

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Details) (USD $)	Jan. 31, 2015
In Thousands, unless otherwise specified
Accounting Policies [Abstract]
Cumulative preferred dividends	$10,775

Acquisitions_and_Divestitures_1

Acquisitions and Divestitures (Details) (Savant Alaska, LLC [Member], USD $)	0 Months Ended
	Dec. 11, 2014	Dec. 11, 2014
Savant Alaska, LLC [Member]
Cash Consideration Paid and Promissory Notes Issued for the Acquisition:
Cash paid	$6,000,000
Promissory notes	3,000,000
Consideration paid	9,000,000
Preliminary Allocation of Assets Acquired and Liabilities Assumed:
Current assets	9,772,000	9,772,000
Proved oil and gas properties	1,840,000	1,840,000
Crude oil pipeline	585,000	585,000
Support equipment	592,000	592,000
Other assets	408,000	408,000
Current liabilities	-2,757,000	-2,757,000
Asset retirement obligation	-1,440,000	-1,440,000
Fair value of assets acquired and liabilities assumed	$9,000,000	$9,000,000

Acquisitions_and_Divestitures_2

Acquisitions and Divestitures (Details 1) (Savant Alaska, LLC [Member], USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Jan. 31, 2015	Jan. 31, 2014	Jan. 31, 2015	Jan. 31, 2014
Savant Alaska, LLC [Member]
Business Acquisition [Line Items]
Revenues	$21,737	$22,747	$83,322	$67,892
Net loss attributable to common shareholders	($159,430)	($5,219)	($344,158)	($16,622)
Net loss per common share, basic and diluted (in dollars per share)	($3.42)	($0.12)	($7.43)	($0.38)

Acquisitions_and_Divestitures_3

Acquisitions and Divestitures (Details 2) (Anchor Point Pipeline [Member], USD $)	0 Months Ended
In Thousands, unless otherwise specified	Aug. 08, 2014
Preliminary Allocation of Assets Acquired and Liabilities Assumed:
Natural gas pipeline and pipeline support equipment	$5,687
Asset retirement obligation	-241
Fair value of assets acquired and liabilities assumed	5,446
Series D Preferred Stock [Member]
Consideration Issued for Acquisition:
Series D Preferred Stock	$5,446

Acquisitions_and_Divestitures_4

Acquisitions and Divestitures (Details Textual) (USD $)	0 Months Ended	1 Months Ended	9 Months Ended
	Dec. 11, 2014	Jan. 31, 2015	Jan. 31, 2015
	mi	bbl
	gal
	MW
	tank
	facility
	Pipeline
	airstrip
	Well
	bbl
Savant Alaska, LLC [Member]
Business Acquisition [Line Items]
Consideration paid	$9,000,000
Cash paid	6,000,000
Acquisition-related costs	396,000
Net loss	-1,560,000
Working interest acquired (percent)	67.50%
Ownership in nearby leases (percent)	100.00%
ASRC Exploration, LLC working interest ownership (percent)	32.50%
Daily processing capacity (in barrels per day)	38,500
Number of diesel storage tanks	1
Diesel storage tank holding capacity (in gallons)	500,000
Power generation (in megawatts)	20
Number of grind and inject solid waste disposal facilities	1
Number of Class 1 disposal wells	1
Number of airstrips	1
Airstrip length (in miles)	1
Number of pipelines	2
Length of pipeline (in miles)	25
Gross BOPD production (in barrels per day)		1,000
Net BOPD production (in barrels per day)		600
Goodwill	0
Savant Promissory Note [Member]
Business Acquisition [Line Items]
Savant promissory notes payable		2,000,000	2,000,000
Number of promissory notes issued	3
Amount issued per note (in dollars per note)	1,000,000
Savant Promissory Note [Member] | Savant Alaska, LLC [Member]
Business Acquisition [Line Items]
Savant promissory notes payable	3,000,000
Number of promissory notes issued	3
Amount issued per note (in dollars per note)	1,000,000
Repayments of promissory note			$1,000,000

Acquisitions_and_Divestitures_5

Acquisitions and Divestitures (Details Textual 1) (USD $)	0 Months Ended
	Aug. 08, 2014	Jan. 31, 2015	Aug. 25, 2014	Apr. 30, 2014
Anchor Point Pipeline [Member]
Business Acquisition [Line Items]
Goodwill	$0
Series D Preferred Stock [Member]
Business Acquisition [Line Items]
Shares issued (in shares)		3,330,608	750,000	1,070,448
Series D Preferred Stock [Member] | Anchor Point Pipeline [Member]
Business Acquisition [Line Items]
Shares issued (in shares)	213,586
Series D Preferred Stock purchase consideration	$5,446,000

Acquisitions_and_Divestitures_6

Acquisitions and Divestitures (Details Textual 2) (USD $)	9 Months Ended		0 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2015	Jan. 31, 2014	Nov. 20, 2014
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of assets	$4,191	$0
Tennessee Divestiture [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of assets			$4,191

Major_Customers_and_Concentrat1

Major Customers and Concentrations of Credit Risk (Details) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
	Jan. 31, 2015	Jan. 31, 2014	Jan. 31, 2015	Jan. 31, 2014	Apr. 30, 2014
Concentration Risk [Line Items]
Credit losses	$0	$0	$0	$0
FDIC uninsured amount	1,378,000		1,378,000
FDIC insured amount	$250,000		$250,000
Revenue [Member] | Customer One [Member]
Concentration Risk [Line Items]
Concentration risk (percent)	72.00%	95.00%	79.00%	93.00%
Revenue [Member] | Customer Two [Member]
Concentration Risk [Line Items]
Concentration risk (percent)	19.00%	0.00%	10.00%	0.00%
Accounts receivable [Member] | Customer One [Member]
Concentration Risk [Line Items]
Concentration risk (percent)			14.00%		5.00%
Accounts receivable [Member] | Customer Two [Member]
Concentration Risk [Line Items]
Concentration risk (percent)			11.00%

Related_Party_Transactions_Det

Related Party Transactions (Details) (USD $)	3 Months Ended	9 Months Ended	0 Months Ended
In Thousands, except Share data, unless otherwise specified	Jan. 31, 2015	Jan. 31, 2015	Dec. 09, 2014	Mar. 09, 2015
Immediate Family Member of Management or Principal Owner [Member]
Related Party Transaction [Line Items]
Amount paid to related party	$617	$2,320
Affiliated Entity [Member]
Related Party Transaction [Line Items]
Annual compensation			$275
Affiliated Entity [Member] | Subsequent Event [Member]
Related Party Transaction [Line Items]
Option awarded (in shares)				100,000
Exercise price (in dollars per share)				$1.35

Oil_and_Gas_Properties_and_Equ2

Oil and Gas Properties and Equipment (Details) (USD $)	Jan. 31, 2015	Apr. 30, 2014
In Thousands, unless otherwise specified
Property costs:
Proved property	$476,694	$467,740
Unproved property	47,984	243,230
Total property costs	524,678	710,970
Less: Accumulated depletion	-334,956	-66,143
Oil and gas properties, net	$189,722	$644,827

Oil_and_Gas_Properties_and_Equ3

Oil and Gas Properties and Equipment (Details 1) (USD $)	Jan. 31, 2015	Apr. 30, 2014
In Thousands, unless otherwise specified
Equipment
Equipment, gross	$62,877	$45,707
Less: Accumulated depreciation	-11,186	-10,338
Equipment, net	51,691	35,369
Machinery and Equipment [Member]
Equipment
Equipment, gross	2,821	7,759
Vehicles [Member]
Equipment
Equipment, gross	1,425	1,877
Buildings [Member]
Equipment
Equipment, gross	2,043	2,726
Office Equipment [Member]
Equipment
Equipment, gross	1,054	1,108
Leasehold Improvements [Member]
Equipment
Equipment, gross	676	527
Drilling Rigs [Member]
Equipment
Equipment, gross	44,581	30,210
Capital Lease Asset [Member]
Equipment
Equipment, gross	4,022	1,500
Pipeline and Pipeline Support Assets [Member]
Equipment
Equipment, gross	$6,255	$0

Oil_and_Gas_Properties_and_Equ4

Oil and Gas Properties and Equipment (Details 2) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2015	Jan. 31, 2014
Property, Plant and Equipment [Abstract]
Depletion of oil and gas related assets	$53,240	$19,158
Depreciation and amortization of equipment	3,361	3,194
Total	$56,601	$22,352

Oil_and_Gas_Properties_and_Equ5

Oil and Gas Properties and Equipment (Details Textual) (USD $)	9 Months Ended		0 Months Ended		3 Months Ended	6 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2015	Jan. 31, 2014	Jan. 31, 2015	Oct. 31, 2014	Jan. 31, 2015	Jan. 31, 2015
Property, Plant and Equipment [Line Items]
Charge to exploration expense	$242,980	$157
Capital lease obligation	3,250
Oil and Gas Properties [Member]
Property, Plant and Equipment [Line Items]
Impairment of proved properties			81,480	112,414
Impairment of unproved properties			67,586	152,887
Redoubt Unit [Member] | Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member]
Property, Plant and Equipment [Line Items]
Proved properties fair value	42,044		42,044		42,044	42,044
Unproved properties fair value	2,318		2,318		2,318	2,318
West McArthur River Unit [Member] | Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member]
Property, Plant and Equipment [Line Items]
Proved properties fair value	75,433		75,433		75,433	75,433
Unproved properties fair value	1,252		1,252		1,252	1,252
Olson Creek No. 1 and Otter No. 1 [Member] | Oil and Gas Properties [Member]
Property, Plant and Equipment [Line Items]
Charge to exploration expense					40,443
Olson Creek No. 2 [Member] | Oil and Gas Properties [Member]
Property, Plant and Equipment [Line Items]
Charge to exploration expense						18,800
Rig 37 [Member] | Oil and Gas Properties [Member]
Property, Plant and Equipment [Line Items]
Payment for rig	7,000
Rig 36 [Member]
Property, Plant and Equipment [Line Items]
Capital lease obligation	3,250
Tennessee Divestiture [Member]
Property, Plant and Equipment [Line Items]
Impairment charge	5,524			1,319	4,205
Fair value of Tennessee assets	2,331		2,331		2,331	2,331
Fair value of Tennessee liabilities	$950		$950		$950	$950

Derivative_Instruments_Details

Derivative Instruments (Details) (Not Designated as Hedging Instrument [Member], Crude Oil [Member], Swap [Member])	9 Months Ended
	Jan. 31, 2015
	bbl
2015 [Member]
Derivative [Line Items]
Open positions (in barrels)	191,400
Weighted average fixed price (in dollars per barrel)	97.09
2016 [Member]
Derivative [Line Items]
Open positions (in barrels)	787,600
Weighted average fixed price (in dollars per barrel)	95.36
2017 [Member]
Derivative [Line Items]
Open positions (in barrels)	232,600
Weighted average fixed price (in dollars per barrel)	93.97

Derivative_Instruments_Details1

Derivative Instruments (Details 1) (Not Designated as Hedging Instrument [Member], Commodity Contract [Member], USD $)	Jan. 31, 2015	Apr. 30, 2014
In Thousands, unless otherwise specified
Derivatives, Fair Value [Line Items]
Commodity derivative asset	$41,540	$114
Commodity derivative liability		-7,321
Short-term Portion of Derivative Instruments [Member]
Derivatives, Fair Value [Line Items]
Commodity derivative asset	29,513	88
Commodity derivative liability		-3,315
Long-term Portion of Derivative Instruments [Member]
Derivatives, Fair Value [Line Items]
Commodity derivative asset	12,027	26
Commodity derivative liability		($4,006)

Derivative_Instruments_Details2

Derivative Instruments (Details 2) (Not Designated as Hedging Instrument [Member], Commodity Contract [Member], USD $)	Jan. 31, 2015		Apr. 30, 2014
In Thousands, unless otherwise specified
Not Designated as Hedging Instrument [Member] | Commodity Contract [Member]
Derivatives, Fair Value [Line Items]
Gross derivative assets presented on balance sheet	$41,540		$114
Netting adjustments	0	[1]	-114	[1]
Net derivative assets	41,540		0
Gross derivative liabilities presented on balance sheet			-7,321
Netting adjustments			114	[1]
Net derivative liabilities			($7,207)
[1]	The Company has an agreement in place that allows for the financial right of offset for derivative assets and derivative liabilities at settlement or in the event of default under the agreement.

Derivative_Instruments_Details3

Derivative Instruments (Details 3) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2015	Jan. 31, 2014	Jan. 31, 2015	Jan. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Gain (loss) on derivatives, net	$39,330	$1,677	$55,516	($5,589)

Fair_Value_Measurements_Detail

Fair Value Measurements (Details) (Commodity Contract [Member], Not Designated as Hedging Instrument [Member], USD $)	Jan. 31, 2015	Apr. 30, 2014
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commodity derivative asset	$41,540	$114
Commodity derivative liability		-7,321
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commodity derivative asset	41,540	114
Commodity derivative liability	0	-7,321
Total	$41,540	($7,207)

Debt_Details

Debt (Details) (USD $)	Jan. 31, 2015	Apr. 30, 2014
Long-term Debt, Excluding Current Maturities [Abstract]
Capital lease obligation	$2,756,000
Series B Preferred Stock	2,382,000	2,325,000
Total debt obligations	225,805,000	184,202,000
Less: Current maturities	-29,553,000	-9,459,000
Total debt less current maturities	196,252,000	174,743,000
Savant Promissory Note [Member]
Long-term Debt, Excluding Current Maturities [Abstract]
Savant promissory notes payable	2,000,000
Gunsight Promissory Note [Member]
Long-term Debt, Excluding Current Maturities [Abstract]
Gunsight promissory note payable		950,000
Line of Credit [Member] | Second Lien Credit Facility [Member]
Long-term Debt, Excluding Current Maturities [Abstract]
Credit facility amount	175,000,000	175,000,000
Debt discount	-2,639,000	-3,296,000
Line of Credit [Member] | First Lien RBL [Member]
Long-term Debt, Excluding Current Maturities [Abstract]
Credit facility amount	44,000,000
Line of Credit [Member] | Apollo Senior Secured Credit Facility [Member]
Long-term Debt, Excluding Current Maturities [Abstract]
Prepayment and extension fee note payable	$2,306,000	$9,223,000

Debt_Details_1

Debt (Details 1) (Line of Credit [Member], First Lien RBL [Member], London Interbank Offered Rate (LIBOR) [Member])	9 Months Ended
	Jan. 31, 2015
Range 1 [Member]
Line of Credit Facility [Line Items]
Spread above LIBOR (percent)	3.00%
Undrawn commitment fee rate (percent)	0.50%
Range 2 [Member]
Line of Credit Facility [Line Items]
Spread above LIBOR (percent)	3.25%
Undrawn commitment fee rate (percent)	0.50%
Range 3 [Member]
Line of Credit Facility [Line Items]
Spread above LIBOR (percent)	3.50%
Undrawn commitment fee rate (percent)	0.75%
Range 4 [Member]
Line of Credit Facility [Line Items]
Spread above LIBOR (percent)	3.75%
Undrawn commitment fee rate (percent)	0.75%
Range 5 [Member]
Line of Credit Facility [Line Items]
Spread above LIBOR (percent)	4.00%
Undrawn commitment fee rate (percent)	0.75%

Debt_Details_2

Debt (Details 2) (Line of Credit [Member], First Lien RBL [Member])	9 Months Ended
	Jan. 31, 2015
Range 1 [Member]
Line of Credit Facility [Line Items]
Lower range of borrowing base utilization (percent)	0.00%
Higher range of borrowing base utilization (percent)	24.00%
Range 2 [Member]
Line of Credit Facility [Line Items]
Lower range of borrowing base utilization (percent)	25.00%
Higher range of borrowing base utilization (percent)	49.00%
Range 3 [Member]
Line of Credit Facility [Line Items]
Lower range of borrowing base utilization (percent)	50.00%
Higher range of borrowing base utilization (percent)	74.00%
Range 4 [Member]
Line of Credit Facility [Line Items]
Lower range of borrowing base utilization (percent)	75.00%
Higher range of borrowing base utilization (percent)	89.00%
Range 5 [Member]
Line of Credit Facility [Line Items]
Lower range of borrowing base utilization (percent)	90.00%
Higher range of borrowing base utilization (percent)	100.00%

Debt_Details_3

Debt (Details 3) (Series B Preferred Stock [Member], Cumulative Preferred Stock Subject to Mandatory Redemption [Member], USD $)	0 Months Ended			9 Months Ended	0 Months Ended
	Jan. 30, 2015	Sep. 02, 2014	Jul. 28, 2014	Jan. 31, 2015	Mar. 02, 2015
Preferred Stock
Declared dividend (in dollars per share)	$5.95		$6.05
Cumulative dividend rate per annum (percent)				12.00%
Par value (in dollars per share)				$100
Dividend paid (in dollars per share)		$6.05
Subsequent Event [Member]
Preferred Stock
Dividend paid (in dollars per share)					$5.95

Debt_Details_Textual

Debt (Details Textual) (USD $)	0 Months Ended							9 Months Ended
	Feb. 03, 2014	Dec. 10, 2014	Dec. 31, 2014	Dec. 11, 2014	Aug. 01, 2014	Jun. 24, 2014	Jun. 02, 2014	Jan. 31, 2015	Apr. 30, 2014
Line of Credit Facility [Line Items]
Unamortized deferred financing costs								$3,364,000	$803,000
Line of Credit [Member] | Prior Credit Facility [Member]
Line of Credit Facility [Line Items]
Refinanced credit facility	100,000,000
Repayments on lines of credit	75,306,000
Line of Credit [Member] | Second Lien Credit Facility [Member]
Line of Credit Facility [Line Items]
Credit facility	175,000,000
Borrowing base	175,000,000
Amount borrowed	175,000,000
Original issue discount (percent)	2.00%
Maturity (in years)	4 years
Amount used to finance acquisition costs	56,577,000
Amount used to retire notes payable obligation	3,071,000
Preferred stock issuable		25,000,000
Stated liquidation preference		50,000,000
Properties mandatorily subject to mortgage (percent)	80.00%	90.00%
Net proceeds required in agreement		20,000,000
Line of Credit [Member] | Second Lien Credit Facility [Member] | London Interbank Offered Rate (LIBOR) [Member]
Line of Credit Facility [Line Items]
Variable rate (percent)	9.75%
LIBOR floor rate (percent)	2.00%
Line of Credit [Member] | Second Lien Credit Facility [Member] | Fair Value, Inputs, Level 3 [Member]
Line of Credit Facility [Line Items]
Fair value of outstanding balance								171,525,000	176,785,000
Line of Credit [Member] | Second Lien Credit Facility [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Increase to interest rate (percent)		1.00%
Line of Credit [Member] | Second Lien Credit Facility [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Increase to interest rate (percent)		2.00%
Line of Credit [Member] | First Lien RBL [Member]
Line of Credit Facility [Line Items]
Credit facility		50,000,000
Borrowing base							60,000,000
Amount borrowed			5,000,000	3,000,000	16,000,000	10,000,000	20,000,000
Original issue discount (percent)							1.00%
Revolving credit facility							250,000,000
Repayments on lines of credit								10,000,000
Preferred stock issuable		25,000,000
Stated liquidation preference		50,000,000
Properties mandatorily subject to mortgage (percent)		90.00%					80.00%
Potential maximum borrowing base		$40,000,000

Debt_Details_Textual_1

Debt (Details Textual 1) (Savant Promissory Note [Member], USD $)	Jan. 31, 2015	Dec. 11, 2014
		Note
Savant Promissory Note [Member]
Short-term Debt [Line Items]
Number of promissory notes issued		3
Amount issued per note (in dollars per note)		1,000,000
Savant promissory notes payable	$2,000,000
Default interest rate (percent)		1.50%

Debt_Details_Textual_2

Debt (Details Textual 2) (Fair Value, Inputs, Level 2 [Member], Cumulative Preferred Stock Subject to Mandatory Redemption [Member], Series B Preferred Stock [Member], USD $)	Jan. 31, 2015	Apr. 30, 2014
In Thousands, unless otherwise specified
Fair Value, Inputs, Level 2 [Member] | Cumulative Preferred Stock Subject to Mandatory Redemption [Member] | Series B Preferred Stock [Member]
Preferred Stock
Fair value	$2,075	$2,197

Asset_Retirement_Obligations_D

Asset Retirement Obligations (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2015	Jan. 31, 2014	Jan. 31, 2015	Jan. 31, 2014
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset retirement obligation, as of April 30,			$22,872	$19,890
Additions			2,206	196
Revisions			-100	0
Sold wells			-1,495	0
Accretion expense	370	305	1,067	903
Settlements			-121	-22
North Fork properties purchase price adjustment			159	0
Asset retirement obligation, as of January 31,	$24,588	$20,967	$24,588	$20,967

StockBased_Compensation_Detail

Stock-Based Compensation (Details) (USD $)	9 Months Ended
	Jan. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Beginning balance at April 30, 2014 (in shares)	15,021,347
Beginning balance at April 30, 2014, weighted average exercise price (in dollars per share)	$4.99
Granted (in shares)	2,720,500
Granted, weighted average price (in dollars per share)	$4.53
Exercised (in shares)	-329,939
Exercised, weighted average price (in dollars per share)	$4.37
Cancelled (in shares)	-1,380,460
Cancelled, weighted average price (in dollars per share)	$4.95
Ending balance (in shares)	16,031,448
Ending balance, weighted average exercise price (in dollars per share)	$4.93
Options and warrants exercisable at January 31, 2015 (in shares)	13,760,634
Options and warrants exercisable at January 31, 2015, weighted average price (in dollars per share)	$4.96

StockBased_Compensation_Detail1

Stock-Based Compensation (Details 1) (USD $)	9 Months Ended
	Jan. 31, 2015
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number outstanding (in shares)	16,031,448
Weighted average remaining contractural life (in years)	3 years 10 months 24 days
Weighted average exercise price (in dollars per share)	$4.93
Number exercisable (in shares)	13,760,634
Weighted average exercise price (in dollars per share)	$4.96
$0.01 to $1.24 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number outstanding (in shares)	1,361,000
Weighted average remaining contractural life (in years)	1 year 3 months 18 days
Weighted average exercise price (in dollars per share)	$0.63
Number exercisable (in shares)	1,311,000
Weighted average exercise price (in dollars per share)	$0.61
$2.00 to $4.99 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number outstanding (in shares)	3,673,001
Weighted average remaining contractural life (in years)	7 years
Weighted average exercise price (in dollars per share)	$4.04
Number exercisable (in shares)	2,227,687
Weighted average exercise price (in dollars per share)	$3.77
$5.15 to $5.53 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number outstanding (in shares)	4,137,447
Weighted average remaining contractural life (in years)	2 years 2 months 12 days
Weighted average exercise price (in dollars per share)	$5.32
Number exercisable (in shares)	3,641,947
Weighted average exercise price (in dollars per share)	$5.33
$5.68 to $5.94 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number outstanding (in shares)	3,435,000
Weighted average remaining contractural life (in years)	5 years 9 months 18 days
Weighted average exercise price (in dollars per share)	$5.90
Number exercisable (in shares)	3,195,000
Weighted average exercise price (in dollars per share)	$5.92
$6.00 to $6.95 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number outstanding (in shares)	3,425,000
Weighted average remaining contractural life (in years)	1 year 10 months 24 days
Weighted average exercise price (in dollars per share)	$6.13
Number exercisable (in shares)	3,385,000
Weighted average exercise price (in dollars per share)	$6.12

StockBased_Compensation_Detail2

Stock-Based Compensation (Details 2) (USD $)	9 Months Ended
	Jan. 31, 2015
$0.01 to $1.24 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range, lower limit (in dollars per share)	$0.01
Exercise price range, upper limit (in dollars per share)	$1.24
$2.00 to $4.99 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range, lower limit (in dollars per share)	$2
Exercise price range, upper limit (in dollars per share)	$4.99
$5.15 to $5.53 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range, lower limit (in dollars per share)	$5.15
Exercise price range, upper limit (in dollars per share)	$5.53
$5.68 to $5.94 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range, lower limit (in dollars per share)	$5.68
Exercise price range, upper limit (in dollars per share)	$5.94
$6.00 to $6.95 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range, lower limit (in dollars per share)	$6
Exercise price range, upper limit (in dollars per share)	$6.95

StockBased_Compensation_Detail3

Stock-Based Compensation (Details 3)	9 Months Ended
	Jan. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Unvested at April 30, 2014 (in shares)	465,432
Granted (in shares)	945,655
Vested (in shares)	-1,182,587
Cancelled (in shares)	-28,000
Unvested at January 31, 2015 (in shares)	200,500

StockBased_Compensation_Detail4

Stock-Based Compensation (Details Textual) (USD $)	3 Months Ended		9 Months Ended		0 Months Ended
In Thousands, except Share data, unless otherwise specified	Jan. 31, 2015	Jan. 31, 2014	Jan. 31, 2015	Jan. 31, 2014	Oct. 30, 2014	Apr. 16, 2014	Apr. 30, 2014	Apr. 30, 2010	Apr. 30, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee share-based compensation expense	$703	$1,343	$10,242	$4,368
Nonemployee expense	$41	$203	$615	$752
2010 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized (in shares)								3,000,000
Shares available for grant (in shares)	187,500		187,500				2,500
2011 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized (in shares)									8,250,000
Additional shares authorized (in shares)					2,500,000	5,000,000
Shares available for grant (in shares)	3,157,256		3,157,256				3,132,078

Stockholders_Equity_Details

Stockholders' Equity (Details) (USD $)	0 Months Ended					9 Months Ended	0 Months Ended
	Jan. 30, 2015	Dec. 01, 2014	Oct. 29, 2014	Sep. 02, 2014	Jul. 28, 2014	Jan. 31, 2015	Mar. 02, 2015
Series C Preferred Stock [Member]
Class of Stock [Line Items]
Declared dividend (in dollars per share)	$0.67		$0.67		$0.67
Cumulative dividend rate per annum (percent)						10.75%
Par value (in dollars per share)						$25
Dividend paid (in dollars per share)		$0.67		$0.67
Series C Preferred Stock [Member] | Subsequent Event [Member]
Class of Stock [Line Items]
Dividend paid (in dollars per share)							$0.67
Series D Preferred Stock [Member]
Class of Stock [Line Items]
Declared dividend (in dollars per share)	$0.66		$0.66		$0.66
Cumulative dividend rate per annum (percent)						10.50%
Par value (in dollars per share)						$25
Dividend paid (in dollars per share)		$0.66		$0.66
Series D Preferred Stock [Member] | Subsequent Event [Member]
Class of Stock [Line Items]
Dividend paid (in dollars per share)							$0.66

Stockholders_Equity_DetailsTex

Stockholders' Equity (DetailsTextual)	9 Months Ended
	Jan. 31, 2015	Apr. 30, 2014
Stockholders' Equity Note [Abstract]
Shares outstanding (in shares)	46,662,223	45,756,697
Shares issued (in shares)	905,526
Shares issued for compensation (in shares)	575,587
Exercise of equity rights (in shares)	329,939

Stockholders_Equity_Details_Te

Stockholders' Equity (Details Textual 1) (USD $)	9 Months Ended		0 Months Ended
In Thousands, except Share data, unless otherwise specified	Jan. 31, 2015	Jan. 31, 2014	Aug. 25, 2014	Apr. 30, 2014
Class of Stock [Line Items]
Issuance costs	$1,781	$3,893
Series C Preferred Stock [Member]
Class of Stock [Line Items]
Shares issued during period (in shares)	180,032
Cumulative dividend rate per annum (percent)	10.75%
Redemption value (in dollars per share)	$25
Net proceeds	1,799
Dividend yield (percent)	27.00%
Redemption amount	4,583
Fair value of preferred stock	41,373			77,976
Series D Preferred Stock [Member]
Class of Stock [Line Items]
Shares issued during period (in shares)	1,296,574
Cumulative dividend rate per annum (percent)	10.50%
Redemption value (in dollars per share)	$25
Net proceeds	11,753		17,023
Dividend yield (percent)	29.00%
Redemption amount	32,698
Liquidation preference (in dollars per share)	$25
Shares issued (in shares)	3,330,608		750,000	1,070,448
Price per share (in dollars per share)			$24.50
Gross proceeds			18,375
Issuance costs			1,352
Fair value of preferred stock	$36,670			$31,330

Income_Taxes_Details

Income Taxes (Details) (USD $)	3 Months Ended	9 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2015	Jan. 31, 2015
Income Tax Disclosure [Abstract]
Additional valuation allowance	$64,273
Effective tax rate (percent)		28.00%
Federal statutory rate (percent)		35.00%
Income taxes paid		0
Significant payments expected	$0	$0

Alaska_Production_Credits_Deta

Alaska Production Credits (Details) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2015
State Production Credit Receivable, Annual Loss Credits [Roll Forward]
Balance, April 30, 2014	$49,121
Alaska carried-forward annual loss credits, net	24,240	[1]
Applications for expenditure and exploration based credits	45,979	[1]
Cash collections for expenditure and exploration based credits	-56,012
Balance, January 31, 2015	$63,328
[1]	Applications for carried-forward annual loss credits and for expenditure and exploration based credits are recorded net of established reserves and also include revisions to prior period applications, if applicable.

Alaska_Production_Credits_Deta1

Alaska Production Credits (Details Textual) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2015		Apr. 30, 2014
Alaska Production Tax Credits [Line Items]
Net carried-forward annual loss credits	$24,240	[1]
Expenditure and exploration credits	80,297
Alaska production credits receivable, net	$63,328		$49,121
43.55.023(a)(1) [Member]
Alaska Production Tax Credits [Line Items]
Alaska capital expenditure credit (percent)	20.00%
43.55.023(1)(1) [Member]
Alaska Production Tax Credits [Line Items]
Alaska capital expenditure credit (percent)	40.00%
43.55.023(a)(2) [Member]
Alaska Production Tax Credits [Line Items]
Alaska capital exploration credit (percent)	20.00%
43.55.023(1)(2) [Member]
Alaska Production Tax Credits [Line Items]
Alaska capital exploration credit (percent)	40.00%
43.55.023(b) [Member]
Alaska Production Tax Credits [Line Items]
Alaska carried-forward annual loss credit (percent)	25.00%
43.55.025 [Member]
Alaska Production Tax Credits [Line Items]
Seismic exploration credits (percent)	40.00%
[1]	Applications for carried-forward annual loss credits and for expenditure and exploration based credits are recorded net of established reserves and also include revisions to prior period applications, if applicable.

Litigation_Details

Litigation (Details) (USD $)	0 Months Ended		9 Months Ended	0 Months Ended
	Jun. 03, 2014	17-May-11	Jan. 31, 2015	Feb. 07, 2014	Mar. 09, 2015	Feb. 03, 2015	29-May-13
Loss Contingencies [Line Items]
Damages sought, minimum		$3,000,000
Damages sought for loss of vested warrants		2,687,000
Reimbursement due from plaintiff	9,000
Gain related to settlement			113,000
Estimated possible loss							1,889,000
Indemnification Agreement [Member]
Loss Contingencies [Line Items]
Litigation settlement				500,000
Subsequent Event [Member]
Loss Contingencies [Line Items]
Litigation settlement					($5,463,000)	$2,950,000

Subsequent_Events_Details

Subsequent Events (Details) (USD $)	0 Months Ended	9 Months Ended	0 Months Ended
	Sep. 02, 2014	Jan. 31, 2015	Mar. 02, 2015	Dec. 01, 2014
Series B Preferred Stock [Member] | Cumulative Preferred Stock Subject to Mandatory Redemption [Member]
Subsequent Event [Line Items]
Dividend paid (in dollars per share)	$6.05
Cumulative dividend rate per annum (percent)		12.00%
Par value (in dollars per share)		$100
Series B Preferred Stock [Member] | Cumulative Preferred Stock Subject to Mandatory Redemption [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Dividend paid (in dollars per share)			$5.95
Series C Preferred Stock [Member]
Subsequent Event [Line Items]
Dividend paid (in dollars per share)	$0.67			$0.67
Cumulative dividend rate per annum (percent)		10.75%
Par value (in dollars per share)		$25
Series C Preferred Stock [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Dividend paid (in dollars per share)			$0.67
Series D Preferred Stock [Member]
Subsequent Event [Line Items]
Dividend paid (in dollars per share)	$0.66			$0.66
Cumulative dividend rate per annum (percent)		10.50%
Par value (in dollars per share)		$25
Series D Preferred Stock [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Dividend paid (in dollars per share)			$0.66

Subsequent_Events_Details_Text

Subsequent Events (Details Textual) (USD $)	0 Months Ended
	Dec. 10, 2014	Mar. 09, 2015	Feb. 03, 2015	Mar. 11, 2015	Feb. 03, 2014
Line of Credit [Member] | First Lien RBL [Member]
Subsequent Event [Line Items]
Preferred stock issuable	$25,000,000
Stated liquidation preference	50,000,000
Credit facility	50,000,000
Line of Credit [Member] | Second Lien Credit Facility [Member]
Subsequent Event [Line Items]
Preferred stock issuable	25,000,000
Stated liquidation preference	50,000,000
Net proceeds required in agreement	20,000,000
Credit facility					175,000,000
Subsequent Event [Member]
Subsequent Event [Line Items]
Litigation settlement		-5,463,000	2,950,000
Subsequent Event [Member] | Line of Credit [Member] | First Lien RBL [Member]
Subsequent Event [Line Items]
Preferred stock issuable				50,000,000
Stated liquidation preference				100,000,000
Net proceeds required in agreement				10,000,000
Credit facility				45,000,000
Increase to interest rate (percent)				1.00%
Subsequent Event [Member] | Line of Credit [Member] | Second Lien Credit Facility [Member]
Subsequent Event [Line Items]
Preferred stock issuable				50,000,000
Stated liquidation preference				100,000,000
Net proceeds required in agreement				$10,000,000