Earnings Per Share - Share-based Compensation (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based awards, exercised or released (in shares)	35,722	395,648	1,372,679	1,158,943
Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options exercised (in shares)	6,953	18,546	27,794	245,847
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options exercised (in shares)	28,769	184,176	1,002,003	362,573
Performance Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options exercised (in shares)	0	192,926	342,882	550,523