Net Income (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2017		Sep. 30, 2017		Jun. 30, 2017		Mar. 31, 2017		Dec. 31, 2016		Sep. 30, 2016		Jun. 30, 2016		Mar. 31, 2016		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Numerator for Basic and Diluted Earnings per Share - [Abstract]
Net Income (Loss)	$ 2,430,468		$ 100,541		$ 23,053		$ 28,517		$ (142,352)		$ (190,000)		$ (292,558)		$ (471,776)		$ 2,582,579	$ (1,096,686)	$ (4,524,515)
Denominator for Basic Earnings per Share - [Abstract]
Weighted Average Shares	575,394		574,783		574,439		573,935		567,337		547,838		547,335		546,715		574,620	553,384	545,697
Denominator for Diluted Earnings per Share - [Abstract]
Adjusted Diluted Weighted Average Shares	579,203		578,736		578,483		578,593		567,337		547,838		547,335		546,715		578,693	553,384	545,697
Net Income (Loss) Per Share [Abstract]
Basic	$ 4.22	[1]	$ 0.17	[1]	$ 0.04	[1]	$ 0.05	[1]	$ (0.25)	[1]	$ (0.35)	[1]	$ (0.53)	[1]	$ (0.86)	[1]	$ 4.49	$ (1.98)	$ (8.29)
Diluted	$ 4.20	[1]	$ 0.17	[1]	$ 0.04	[1]	$ 0.05	[1]	$ (0.25)	[1]	$ (0.35)	[1]	$ (0.53)	[1]	$ (0.86)	[1]	$ 4.46	$ (1.98)	$ (8.29)
Stock Options and Sars [Member]
Potential Dilutive Common Shares -[Abstract]
Common Shares Attributable to Dilutive Effect of Share-Based Payment Arrangments																	1,466	0	0
Antidilutive Securities Excluded from Computation of Earnings Per Share [Abstract]
Anti-dilutive Securities excluded from Diluted Earnings Per Share Calculation																	2,600	10,300	10,200
Restricted Stock/Units and Performance Units/Stock [Member]
Potential Dilutive Common Shares -[Abstract]
Common Shares Attributable to Dilutive Effect of Share-Based Payment Arrangments																	2,607	0	0
Antidilutive Securities Excluded from Computation of Earnings Per Share [Abstract]
Anti-dilutive Securities excluded from Diluted Earnings Per Share Calculation																		4,500

[1] The sum of quarterly net income (loss) per share may not agree with total year net income (loss) per share as each quarterly computation is based on the weighted average of common shares outstanding.