Segment Information - Summary of Segments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Segment Reporting Information [Line Items]
Revenues from external customers	$ 761,890	$ 253,093	$ 1,353,008	$ 628,865
Gross profit (loss)	63,128	7,607	99,304	25,994
Ecommerce
Segment Reporting Information [Line Items]
Revenues from external customers	579,663	175,568	1,001,971	408,740
Gross profit (loss)	49,638	7,219	81,475	21,486
Wholesale
Segment Reporting Information [Line Items]
Revenues from external customers	128,108	50,921	246,132	106,497
Gross profit (loss)	8,516	(543)	8,234	(1,838)
TDA
Segment Reporting Information [Line Items]
Revenues from external customers	50,759	26,318	98,346	112,902
Gross profit (loss)	3,148	864	5,939	6,124
All Other
Segment Reporting Information [Line Items]
Revenues from external customers	3,360	286	6,559	726
Gross profit (loss)	$ 1,826	$ 67	$ 3,656	$ 222