BUSINESS COMBINATIONS BUSINESS COMBINATIONS (Details) $ in Thousands, shares in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2016 USD ($)	Dec. 31, 2016 USD ($) a Wells shares	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Business Acquisition [Line Items]
Oil and gas producing wells, gross | Wells		2,900
Business Combination, Consideration Transferred, Equity Interests Issued and Issuable		$ 690,702	$ 0	$ 0
Delaware Basin Acquisition [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross	$ 952,142	952,142
Payments for Deposits Applied to Debt Retirements		$ 40,000
Oil and gas producing wells, gross | Wells		30
Gas and Oil Area, Developed, Gross | a		57,900
Stock Issued During Period, Shares, Acquisitions | shares		9.4
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual		$ 5,600
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual		(1,700)
Business Combination, Consideration Transferred, Equity Interests Issued and Issuable		$ 690,702
Delaware Basin Acquisition, Reeves and Culberson Counties, Texas [Member]
Business Acquisition [Line Items]
Gas and Oil Area, Developed, Gross | a		4,600
Payments to Acquire Oil and Gas Property		$ 120,600