EQUITY - Business Combination and Redeemable Noncontrolling Interest (Details) $ / shares in Units, $ in Thousands			3 Months Ended		7 Months Ended		12 Months Ended
	Nov. 09, 2018 USD ($) $ / shares shares ft³	Aug. 08, 2018 shares	Nov. 08, 2018 shares	Jun. 30, 2017 $ / shares shares	Aug. 07, 2018 shares	Dec. 31, 2016 USD ($)	Dec. 31, 2018 USD ($) shares	Dec. 31, 2017 USD ($) shares
Class of Stock [Line Items]
Capital contributed | $	$ 628,154					$ 0	$ 628,154	$ 0
Number of warrants received (in shares)	18,941,651
Warrant exercise price (in USD per share) | $ / shares	$ 11.50
Warrant issued during period (in shares)	3,182,140
Earn-out consideration, threshold consecutive trading days	30 days
Earn-out consideration, threshold trading days	20 days
Period following transaction closing for redemption	180 days
Redeemable noncontrolling interest, redemption value | $							$ 1,900,000
Redeemable noncontrolling interest, redemption value measurement period							5 days
Measurement One
Class of Stock [Line Items]
Earn-out consideration, measurement in volume (in cubic feet) | ft³	574,380,000,000
Measurement Two
Class of Stock [Line Items]
Earn-out consideration, stock price trigger (in USD per share) | $ / shares	$ 14.00
Measurement Three
Class of Stock [Line Items]
Earn-out consideration, stock price trigger (in USD per share) | $ / shares	$ 16.00
Private Placement
Class of Stock [Line Items]
Number of warrants forfeited (in shares)		3,182,140
Capital contributed | $	$ 572,340
Warrant issued during period (in shares)				6,364,281
Class A Common Stock
Class of Stock [Line Items]
Stock redeemed (in shares)					29,469,858		29,469,858
Number of shares forfeited			0
Number of shares converted			(2,120,000)
Issuance of shares (in shares)	7,313,028
Common stock, shares outstanding (in shares)	74,929,305		67,616,277		65,496,277		74,929,305	37,732,112
Stock issued during period related to contribution agreement	7,313,028
Earn-out consideration of equity interest (in shares)	37,500,000
Common stock, redemption ratio							1
Class A Common Stock | Measurement One
Class of Stock [Line Items]
Earn-out consideration of equity interest (in shares)	12,500,000
Class A Common Stock | Measurement Two
Class of Stock [Line Items]
Earn-out consideration of equity interest (in shares)	12,500,000
Class A Common Stock | Measurement Three
Class of Stock [Line Items]
Earn-out consideration of equity interest (in shares)	12,500,000
Class A Common Stock | Private Placement
Class of Stock [Line Items]
Issuance of shares (in shares)	57,234,023				57,234,023
Offering price (in USD per share) | $ / shares	$ 10.00
Warrant exercise price (in USD per share) | $ / shares				$ 11.50
Class B Common Stock
Class of Stock [Line Items]
Stock redeemed (in shares)					0
Number of shares forfeited		7,313,028	7,313,028
Number of shares converted			2,120,000				2,120,000
Common stock, shares outstanding (in shares)	0		0		9,433,028			9,433,028
Class B Common Stock | Private Placement
Class of Stock [Line Items]
Issuance of shares (in shares)					0
Class C Common Stock
Class of Stock [Line Items]
Stock redeemed (in shares)					0
Number of shares forfeited			0
Issuance of shares (in shares)	250,000,000
Common stock, shares outstanding (in shares)	250,000,000		0		0		250,000,000	0
Stock issued during period related to contribution agreement	250,000,000
Class C Common Stock | Private Placement
Class of Stock [Line Items]
Issuance of shares (in shares)					0
Altus Midstream LP | Apache
Class of Stock [Line Items]
Number of common units received	250,000,000
Limited partners, ownership interest	76.90%						76.90%