Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets.

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Cost incurred related to the gas activities, such as transportation, marketing and processing crude oil, natural gas and refined petroleum products.

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Costs incurred to operate and maintain an entities' wells and related equipment and facilities, including depreciation and applicable operating costs of support equipment and facilities and other costs of operating and maintaining those wells and related equipment and facilities.

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Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Sales and revenues:
Sales and revenues	$ 1,481,823us-gaap_Revenues	$ 762,490us-gaap_Revenues	$ 311,338us-gaap_Revenues	$ 164,981us-gaap_Revenues	$ 480,014us-gaap_Revenues	$ 384,522us-gaap_Revenues	$ 387,144us-gaap_Revenues	$ 61,454us-gaap_Revenues	$ 2,720,632us-gaap_Revenues	$ 1,313,134us-gaap_Revenues	$ 735,718us-gaap_Revenues
Operating expenses:
Lease operating									29,341us-gaap_OilAndGasProductionExpense	9,439us-gaap_OilAndGasProductionExpense	6,243us-gaap_OilAndGasProductionExpense
Gathering, compression, processing, and transportation expense									461,413	218,428	91,094
Depreciation, Depletion and Amortization									477,896	233,876	102,026
General and administrative expense									216,533us-gaap_GeneralAndAdministrativeExpense	425,438us-gaap_GeneralAndAdministrativeExpense	45,284us-gaap_GeneralAndAdministrativeExpense
Other operating expenses									235,715us-gaap_OtherCostAndExpenseOperating	84,746us-gaap_OtherCostAndExpenseOperating
Total									1,420,898us-gaap_OperatingCostsAndExpenses	971,927us-gaap_OperatingCostsAndExpenses
Operating income (loss)	1,027,717us-gaap_OperatingIncomeLoss	381,399us-gaap_OperatingIncomeLoss	(5,303)us-gaap_OperatingIncomeLoss	(104,079)us-gaap_OperatingIncomeLoss	(81,318)us-gaap_OperatingIncomeLoss	222,608us-gaap_OperatingIncomeLoss	248,386us-gaap_OperatingIncomeLoss	(48,469)us-gaap_OperatingIncomeLoss	1,299,734us-gaap_OperatingIncomeLoss	341,207us-gaap_OperatingIncomeLoss	444,015us-gaap_OperatingIncomeLoss
Segment assets	11,573,495us-gaap_Assets				6,613,581us-gaap_Assets				11,573,495us-gaap_Assets	6,613,581us-gaap_Assets
Capital expenditures for segment assets									4,086,568	2,671,573
Exploration and production
Sales and revenues:
Sales and revenues									2,645,148
Gathering and compression
Sales and revenues:
Sales and revenues									95,746
Fresh Water Distribution
Sales and revenues:
Sales and revenues									171,925
Marketing
Sales and revenues:
Sales and revenues									53,604
Operating segments \| Exploration and production
Sales and revenues:
Sales and revenues									2,644,953	1,313,134
Operating expenses:
Lease operating									28,041	9,439
Gathering, compression, processing, and transportation expense									536,879	238,712
Depreciation, Depletion and Amortization									424,684	219,757
General and administrative expense									186,335	391,373
Other operating expenses									128,419	82,787
Total									1,304,358	942,068
Operating income (loss)									1,340,790	371,066
Segment assets	9,920,331				5,859,933				9,920,331	5,859,933
Capital expenditures for segment assets									3,455,079	2,110,358
Operating segments \| Gathering and compression
Sales and revenues:
Sales and revenues									6,810	22,363
Operating expenses:
Gathering, compression, processing, and transportation expense									13,497	2,079
Depreciation, Depletion and Amortization									36,972	11,346
General and administrative expense									22,035	23,124
Other operating expenses									1,973
Total									74,477	36,549
Operating income (loss)									21,269	(14,186)
Segment assets	1,411,470				561,855				1,411,470	561,855
Capital expenditures for segment assets									558,037	389,453
Operating segments \| Fresh Water Distribution
Sales and revenues:
Sales and revenues									15,265	35,871
Operating expenses:
Lease operating									34,737	3,843
Depreciation, Depletion and Amortization									16,240	2,773
General and administrative expense									8,331	10,941
Other operating expenses									1,888	1,959
Total									61,196	19,516
Operating income (loss)									110,729	16,355
Segment assets	422,885				230,247				422,885	230,247
Capital expenditures for segment assets									196,675	203,790
Operating segments \| Marketing
Sales and revenues:
Sales and revenues									53,604
Operating expenses:
Other operating expenses									103,435
Total									103,435
Operating income (loss)									(49,831)
Segment assets	10,456								10,456
Elimination of intersegment transaction
Sales and revenues:
Sales and revenues									(245,791)	(58,234)
Operating expenses:
Lease operating									(33,437)	(3,843)
Gathering, compression, processing, and transportation expense									(88,963)	(22,363)
General and administrative expense									(168)
Total									(122,568)	(26,206)
Operating income (loss)									(123,223)	(32,028)
Segment assets	(191,647)				(38,454)				(191,647)	(38,454)
Capital expenditures for segment assets									(123,223)	(32,028)
Elimination of intersegment transaction \| Exploration and production
Sales and revenues:
Sales and revenues									195
Elimination of intersegment transaction \| Gathering and compression
Sales and revenues:
Sales and revenues									88,936
Elimination of intersegment transaction \| Fresh Water Distribution
Sales and revenues:
Sales and revenues									$ 156,660