Selected Quarterly Financial Data (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Condensed Financial Statements, Captions
Revenues	$ 23,037	$ 27,717	$ 20,089	$ 12,494	$ 127,280	$ 566	$ 376	$ 1,792	$ 83,337	$ 130,014	$ 22,854
Income (Loss) From Operations	(31,330)	(34,933)	(37,021)	(33,871)	88,360	(33,677)	(26,688)	(26,527)	$ (137,155)	$ 1,468	$ (100,366)
Net Income (Loss) Available to Common Stockholders, Basic	$ (32,419)	$ (36,015)	$ (38,112)	$ (34,883)	86,750	$ (35,282)	$ (26,074)	$ (28,076)
Earnings Per Share, Basic and Diluted	$ (0.31)	$ (0.35)	$ (0.37)	$ (0.34)					$ (1.36)	$ (0.05)	$ (1.31)
Weighted Average Number of Shares Outstanding, Basic and Diluted	104,052	103,885	103,830	103,682					103,863	103,591	76,347
Net Income (Loss) Available to Common Stockholders, Diluted					$ 88,027
Earnings Per Share, Basic					$ 0.84	$ (0.34)	$ (0.27)	$ (0.27)
Earnings Per Share, Diluted					$ 0.76	$ (0.34)	$ (0.27)	$ (0.27)
Weighted Average Number of Shares Outstanding, Basic					103,623	103,616	103,608	103,516
Incremental Common Shares Attributable to Dilutive Effect of Conversion of Debt Securities					10,365
Weighted Average Number of Shares Outstanding, Diluted					115,764	103,616	103,608	103,516
Interest on Convertible Debt, Net of Tax					$ 1,277
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements					1,776