Segment Information - Summary of Reportable Segments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information [Line Items]
Revenues from external customers	$ 323,005	$ 340,273	$ 951,871	$ 836,229
Gross profit	25,445	15,671	51,439	41,528
Ecommerce
Segment Reporting Information [Line Items]
Revenues from external customers	221,761	178,113	630,501	388,921
Gross profit	19,304	8,774	40,789	21,823
TDA
Segment Reporting Information [Line Items]
Revenues from external customers	37,272	103,106	150,901	281,603
Gross profit	2,798	6,650	9,144	18,830
Wholesale
Segment Reporting Information [Line Items]
Revenues from external customers	63,972	59,054	170,469	165,705
Gross profit	$ 3,343	$ 247	$ 1,506	$ 875