Supplemental Gas Data (unaudited) Capitalized Costs (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Extractive Industries [Abstract]
Intangible Drilling Cost	$ 4,688,497	$ 4,120,283
Proved Gas Properties	1,208,046	1,135,411
Gas Gathering Assets	1,110,977	1,099,047
Unproved Gas Properties	755,590	927,667
Gas Wells and Related Equipment	1,042,000	856,973
Other Gas Assets	73,479	54,395
Total Property, Plant and Equipment	8,878,589	8,193,776
Accumulated Depreciation, Depletion and Amortization	(3,263,221)	(2,475,917)
Net Capitalized Costs	$ 5,615,368	$ 5,717,859

Capitalized Costs, Other Gas Assets

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Drilling Cost

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Amount of accumulated depreciation, depletion, amortization and valuation allowance relating to oil and gas producing activities.

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The sum of capitalized costs relating to oil and gas producing activities before accounting for accumulated depreciation.

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Net amount of capitalized costs relating to oil and gas producing activities.

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Capitalized costs incurred for support equipment and facilities used in oil and gas producing activities (such as seismic equipment, drilling equipment, construction and grading equipment, vehicles, repair shops, warehouses, supply points, camps, and division, district, or field offices).

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Capitalized costs which include those incurred to (1) to drill and equip those exploratory wells and exploratory-type stratigraphic test wells that have found proved reserves and (2) obtain access to proved reserves and provide facilities for extracting, treating, gathering, storing the oil and gas, including the drilling and equipping of development wells and development-type stratigraphic wells and service wells.

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Oil and Gas properties with proved reserves under the successful effort method.

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Oil and Gas properties with unproved reserves under the successful effort method.

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