Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Intangible Drilling Cost	$ 4,900,667	$ 4,688,497
Gas Gathering Equipment	2,505,267	2,463,866
Proved Gas Properties	1,214,416	1,208,046
Gas Wells and Related Equipment	1,102,366	1,042,000
Unproved Gas Properties	765,008	755,590
Surface Land and Other Equipment	222,732	226,285
Other	194,381	187,722
Total Property, Plant and Equipment	10,904,837	10,572,006
Less: Accumulated Depreciation, Depletion and Amortization	3,841,699	3,435,431
Total Property, Plant and Equipment—Net	$ 7,063,138	$ 7,136,575