Supplemental Information On Oil And Gas Exploration And Production Activities (Changes in Standardized Measure of Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Changes In Standardized Measure of Discontinued Future Net Cash Flows [Line Items]
Sales and transfers of oil and gas produced, net of production costs	$ (530,098)	$ (197,559)	$ (194,893)
Net changes in prices, production costs, and development costs	97,716	65,573	108,941
Acquisition of oil and gas reserves in place	14,266	0	0
Extensions and discoveries	790,533	130,826	151,654
Previously estimated development costs incurred during the period	68,227	43,478	10,211
Revisions of previous quantity estimates, less related production costs	(37,801)	(3,591)	(10,504)
Sales of reserves in place	0	0	(214,867)
Accretion of discount	57,847	34,864	37,668
Net changes in income taxes	(295,226)	(30,239)	25,585
Change in production rates and other	683,237	186,473	58,165
Total change in standardized measure of discounted future net cash flows	848,701	229,825	(28,040)
Diamondback Energy, Inc [Member]
Changes In Standardized Measure of Discontinued Future Net Cash Flows [Line Items]
Sales and transfers of oil and gas produced, net of production costs	0	(12,524)	(11,601)
Net changes in prices, production costs, and development costs	0	3,312	(14,596)
Acquisition of oil and gas reserves in place	0	21,968	23,090
Extensions and discoveries	0	39,776	16,969
Previously estimated development costs incurred during the period	0	5,517	19,014
Revisions of previous quantity estimates, less related production costs	0	(9,143)	(4,897)
Accretion of discount	0	4,175	7,803
Net changes in income taxes	0	(12,137)	(26,866)
Change in production rates and other	0	2,862	(8,358)
Total change in standardized measure of discounted future net cash flows	0	(8,339)	558
Equity Method Investment, Change in Ownership	0	(52,145)	0
Grizzly Oil Sands ULC [Member]
Changes In Standardized Measure of Discontinued Future Net Cash Flows [Line Items]
Sales and transfers of oil and gas produced, net of production costs	(4,664)	0	0
Net changes in prices, production costs, and development costs	76,518	0	0
Acquisition of oil and gas reserves in place	0	0	0
Extensions and discoveries	7,107	0	0
Previously estimated development costs incurred during the period	0	0	0
Revisions of previous quantity estimates, less related production costs	(10,659)	0	0
Accretion of discount	14,946	0	0
Net changes in income taxes	9,162	0	0
Change in production rates and other	(25,738)	0	0
Total change in standardized measure of discounted future net cash flows	$ (55,718)	$ 0	$ 0