Earnings per Common Share - Antidilutive Shares (Details) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Antidilutive Shares [Line Items]
Antidilutive shares (in shares)	2,356	760	2,228	443
Stock options
Antidilutive Shares [Line Items]
Antidilutive shares (in shares)	795	0	772	0
Restricted stock units
Antidilutive Shares [Line Items]
Antidilutive shares (in shares)	268	329	295	226
Performance-based restricted stock units
Antidilutive Shares [Line Items]
Antidilutive shares (in shares)	453	431	286	217
Unvested Walmart restricted shares
Antidilutive Shares [Line Items]
Antidilutive shares (in shares)	840	0	875	0