Basic and Diluted Net Income (Loss) Per Share - Performance based stock (Details) - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Antidilutive securities excluded from computation of earnings per share
Anti-dilutive securities excluded from computation of earnings per share	55,650	53,547	5,999
Strike price of the warrants	$ 86.08
Anti-dilutive stock awards
Antidilutive securities excluded from computation of earnings per share
Anti-dilutive securities excluded from computation of earnings per share	1,694	1,870	712
Performance based options
Antidilutive securities excluded from computation of earnings per share
Anti-dilutive securities excluded from computation of earnings per share	5,491	4,312	3,905
Restricted Performance Units
Antidilutive securities excluded from computation of earnings per share
Anti-dilutive securities excluded from computation of earnings per share	2,436	1,336	1,382
Common stock warrants
Antidilutive securities excluded from computation of earnings per share
Anti-dilutive securities excluded from computation of earnings per share	46,029	46,029