Earnings Per Share - Antidilutive Securities (Details) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share
Total anti-dilutive securities	1,340	5,510
Share-based awards
Antidilutive Securities Excluded from Computation of Earnings Per Share
Total anti-dilutive securities	140	330
Convertible note hedge
Antidilutive Securities Excluded from Computation of Earnings Per Share
Total anti-dilutive securities	1,200	0
Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share
Total anti-dilutive securities	0	5,180