Net Income (Loss) Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Basic EPS
Net income (loss) available to common stockholders	$ (16,677)	$ (43,121)	$ (49,965)	$ (80,312)
Weighted average shares
Basic (in shares)	135,036,000	102,444,000	118,897,000	102,405,000
Diluted (in shares)	135,036,000	102,444,000	118,897,000	102,405,000
Income (loss) per share
Basic	$ (0.12)	$ (0.42)	$ (0.42)	$ (0.78)
Diluted	$ (0.12)	$ (0.42)	$ (0.42)	$ (0.78)
Convertible Senior Notes Due March 2028 [Member]
Earnings Per Share (Textual) [Abstract]
Debt Instrument, Interest Rate, Stated Percentage	3.25%		3.25%		3.25%
Stock Options [Member]
Earnings Per Share (Textual) [Abstract]
Number of shares of common stock equivalents related to convertible debt	3,375,337	2,147,989	3,415,129	2,147,390