REORGANIZATION (Details) $ / shares in Units, a in Thousands							2 Months Ended	3 Months Ended		7 Months Ended	9 Months Ended
	Mar. 01, 2017 USD ($) $ / shares shares	Feb. 28, 2017 USD ($) shares	Feb. 27, 2017 USD ($) shares	Feb. 08, 2017 USD ($)	Jan. 11, 2017 bidder	Dec. 09, 2016 USD ($) a	Feb. 28, 2017 USD ($) shares	Sep. 30, 2017 $ / shares shares	Sep. 30, 2016 shares	Sep. 30, 2017 USD ($) $ / shares shares	Sep. 30, 2017 $ / shares	Sep. 30, 2016 USD ($) shares	Dec. 31, 2016
Restructuring Cost and Reserve [Line Items]
Net consideration received for sale of Appalachia Properties		$ 512,472,000								$ 17,777,000
New shares issued in reorganization (in shares) | shares	20,000,000	20,000,000						0		1,195
7 ½% Senior Second Lien Notes due 2022 | Senior Notes
Restructuring Cost and Reserve [Line Items]
Interest rate	7.50%							7.50%		7.50%	7.50%
Aggregate principal amount of senior subordinated notes	$ 225,000,000.0
Predecessor
Restructuring Cost and Reserve [Line Items]
Net consideration received for sale of Appalachia Properties							$ 505,383,000					$ 0
New shares issued in reorganization (in shares) | shares							47,390		12,900			75,100
Predecessor | 1 ¾% Senior Convertible Notes due 2017
Restructuring Cost and Reserve [Line Items]
Interest rate													1.75%
Predecessor | 7 ½% Senior Second Lien Notes due 2022 | Senior Notes
Restructuring Cost and Reserve [Line Items]
Interest rate													7.50%
Predecessor Company's Common Stockholders
Restructuring Cost and Reserve [Line Items]
Warrants issued in reorganization (in shares) | shares	3,500,000
Exercise price of warrants or rights (in usd per share) | $ / shares								$ 42.04		$ 42.04	$ 42.04
Exercise period for warrants											4 years
RSA | Common Stock
Restructuring Cost and Reserve [Line Items]
New shares issued in reorganization (in shares) | shares	20,000,000
RSA | Predecessor
Restructuring Cost and Reserve [Line Items]
Acreage sold in agreement | a						86
Number of additional bidders allowed to participate in competitive bidding | bidder					2
RSA | Tug Hill | Disposal Group, Disposed of by Sale | Predecessor
Restructuring Cost and Reserve [Line Items]
Net consideration received for sale of Appalachia Properties						$ 360,000,000
Loss on contract termination							$ 11,500,000
RSA | EQT Production Company | Disposal Group, Disposed of by Sale | Predecessor
Restructuring Cost and Reserve [Line Items]
Net consideration received for sale of Appalachia Properties			$ 527,000,000	$ 527,000,000
Upward adjustment to the purchase price				$ 16,000,000
RSA | Noteholders
Restructuring Cost and Reserve [Line Items]
Pro rata share of net cash proceeds			$ 100,000,000
Percentage of common stock issued in reorganization			95.00%
RSA | Noteholders | 7 ½% Senior Second Lien Notes due 2022 | Senior Notes
Restructuring Cost and Reserve [Line Items]
Aggregate principal amount of senior subordinated notes			$ 225,000,000
RSA | Noteholders | Common Stock
Restructuring Cost and Reserve [Line Items]
New shares issued in reorganization (in shares) | shares			19,000,000
RSA | Predecessor Company's Common Stockholders
Restructuring Cost and Reserve [Line Items]
Percentage of common stock issued in reorganization			5.00%
RSA | Predecessor Company's Common Stockholders | Common Stock
Restructuring Cost and Reserve [Line Items]
New shares issued in reorganization (in shares) | shares	1,000,000
Warrants issued in reorganization (in shares) | shares	3,500,000
Exercise price of warrants or rights (in usd per share) | $ / shares	$ 42.04
Exercise period for warrants	4 years
RSA | Appalachia regions of Pennsylvania and West Virginia | Predecessor
Restructuring Cost and Reserve [Line Items]
Minimum proceeds from sale property						$ 350,000,000