Revenue from Contracts with Clients and Customers - Summary of Revenues Disaggregated by Revenue Source, Timing of Revenue Recognition and Region (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Revenues:
Disaggregated revenue	$ 294,022	$ 326,160
North America
Revenues:
Disaggregated revenue	247,444	268,149
Europe
Revenues:
Disaggregated revenue	46,578	58,011
Over time
Revenues:
Disaggregated revenue	266,431	291,659
Point-in-time
Revenues:
Disaggregated revenue	27,591	34,501
PFS Operations
Revenues:
Disaggregated revenue	216,399	241,736
PFS Operations | North America
Revenues:
Disaggregated revenue	178,760	194,496
PFS Operations | Europe
Revenues:
Disaggregated revenue	37,639	47,240
PFS Operations | Over time
Revenues:
Disaggregated revenue	189,786	207,385
PFS Operations | Point-in-time
Revenues:
Disaggregated revenue	26,613	34,351
LiveArea Professional Services
Revenues:
Disaggregated revenue	77,623	84,424
LiveArea Professional Services | North America
Revenues:
Disaggregated revenue	68,684	73,653
LiveArea Professional Services | Europe
Revenues:
Disaggregated revenue	8,939	10,771
LiveArea Professional Services | Over time
Revenues:
Disaggregated revenue	76,645	84,274
LiveArea Professional Services | Point-in-time
Revenues:
Disaggregated revenue	978	150
Service fee revenue
Revenues:
Disaggregated revenue	214,382	230,484
Service fee revenue | PFS Operations
Revenues:
Disaggregated revenue	139,490	148,071
Service fee revenue | LiveArea Professional Services
Revenues:
Disaggregated revenue	74,892	82,413
Product revenue, net
Revenues:
Disaggregated revenue	26,613	34,350
Product revenue, net | PFS Operations
Revenues:
Disaggregated revenue	26,613	34,350
Product revenue, net | LiveArea Professional Services
Revenues:
Disaggregated revenue		0
Pass-through revenue
Revenues:
Disaggregated revenue	53,027	61,326
Pass-through revenue | PFS Operations
Revenues:
Disaggregated revenue	50,296	59,315
Pass-through revenue | LiveArea Professional Services
Revenues:
Disaggregated revenue	$ 2,731	$ 2,011