Earnings (Loss) per Common Share - Antidilutive Shares (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Antidilutive Shares [Line Items]
Antidilutive shares (in shares)	2,299	1,228	1,791	780
Stock options
Antidilutive Shares [Line Items]
Antidilutive shares (in shares)	947	0	488	0
Restricted stock units
Antidilutive Shares [Line Items]
Antidilutive shares (in shares)	133	476	175	314
Performance-based restricted stock units
Antidilutive Shares [Line Items]
Antidilutive shares (in shares)	460	752	292	466
Unvested Walmart restricted shares
Antidilutive Shares [Line Items]
Antidilutive shares (in shares)	759	0	836	0