ASSET IMPAIRMENT - Summary of Impairments (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Impaired Long-Lived Assets Held and Used [Line Items]
Asset impairment			$ 220,652	$ 1,292,308	$ 416,801
Assets impairments from discontinued operations			0	0	1,936
Total asset impairments			220,652	1,292,308	418,737
Central Basin Platform
Impaired Long-Lived Assets Held and Used [Line Items]
Asset impairment			187,043	484,848	0
Delaware Basin
Impaired Long-Lived Assets Held and Used [Line Items]
Asset impairment		$ 90,600	21,288	607,303	90,594
Midland Basin
Impaired Long-Lived Assets Held and Used [Line Items]
Asset impairment		$ 25,800	0	0	25,776
San Juan Basin properties
Impaired Long-Lived Assets Held and Used [Line Items]
Asset impairment	$ 7,500		7,519	133,055	230,315
Permian Basin Unproved Leasehold Properties
Impaired Long-Lived Assets Held and Used [Line Items]
Asset impairment			4,762	29,168	64,361
San Juan Basin unproved leasehold properties
Impaired Long-Lived Assets Held and Used [Line Items]
Asset impairment			40	37,934	5,755
North Louisiana/East Texas oil and natural gas properties
Impaired Long-Lived Assets Held and Used [Line Items]
Assets impairments from discontinued operations			$ 0	$ 0	$ 1,936