Net Income (Loss) Per Share (Details 1) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Earnings Per Share [Abstract]
Net income (loss) from continuing operations attributable to the Company’s common stockholders - Basic	$ (13,753)	$ 24,799	$ (112,775)	$ 265,381
Plus (less): effect of participating securities	0	673	0	6,976
Net income (loss) attributable to common stockholders	(13,753)	25,472	(112,775)	272,357
Less: effect of participating securities	0	(673)	0	(6,976)
Net income (loss) from continuing operations attributable to the Company's common stockholders - Diluted	(13,753)	24,799	(112,775)	265,381
Net income (loss) from discontinued operations attributable to the Company’s common stockholders - Basic	(2,193)	(469)	(8,672)	862
Plus (less): effect of participating securities	0	0	0	23
Net income (loss) attributable to common stockholders	(2,193)	(469)	(8,672)	885
Plus (less): effect of participating securities	0	0	0	(23)
Net income (loss) from discontinued operations attributable to the Company's common stockholders - Diluted	(2,193)	(469)	(8,672)	862
Net income (loss) attributable to the Company's common stockholders - Basic	(15,946)	24,343	(121,447)	266,243
Plus (less): effect of participating securities	0	660	0	6,999
Net income (loss) attributable to common stockholders	(15,946)	25,003	(121,447)	273,242
Less: effect of participating securities	0	(660)	0	(6,999)
Net income (loss) attributable to the Company's common stockholders - Diluted	$ (15,946)	$ 24,343	$ (121,447)	$ 266,243
Shares:
Weighted-average shares used to compute basic net income (loss) per share (in shares)	38,959,606	37,270,928	38,060,782	37,815,598
Adjustment to reflect conversion of convertible notes (in shares)	0	7,648,408	0	4,673,989
Adjustment to reflect stock appreciation right conversions (in shares)	0	584,035	0	420,941
Weighted-average shares used to compute diluted net income (loss) per share (in shares)	38,959,606	45,503,371	38,060,782	42,910,528
Net income (loss) per share attributable to common stockholders - Diluted
Continuing operations (in dollars per share)	$ (0.35)	$ 0.55	$ (2.96)	$ 6.18
Discontinued operations (in dollars per share)	(0.06)	(0.01)	(0.23)	0.02
Diluted net income (loss) (in dollars per share)	$ (0.41)	$ 0.53	$ (3.19)	$ 6.20