SEGMENT INFORMATION - Segmented Revenue Disaggregated by Service (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Segment Reporting Information [Line Items]
Revenue from contracts with customers	$ 387,029	$ 343,650
North America
Segment Reporting Information [Line Items]
Revenue from contracts with customers	361,041	324,132
Europe
Segment Reporting Information [Line Items]
Revenue from contracts with customers	25,988	19,518
Marketplace revenue | North America
Segment Reporting Information [Line Items]
Revenue from contracts with customers	291,050	258,776
Consumer connection revenue | North America
Segment Reporting Information [Line Items]
Revenue from contracts with customers	272,353	239,830
Service professional membership subscription revenue | North America
Segment Reporting Information [Line Items]
Revenue from contracts with customers	11,952	13,777
Other revenue | North America
Segment Reporting Information [Line Items]
Revenue from contracts with customers	6,745	5,169
Advertising and other revenue | North America
Segment Reporting Information [Line Items]
Revenue from contracts with customers	69,991	65,356
Advertising and other revenue | Europe
Segment Reporting Information [Line Items]
Revenue from contracts with customers	309	530
Consumer connection revenue | Europe
Segment Reporting Information [Line Items]
Revenue from contracts with customers	22,351	15,689
Service professional membership subscription revenue | Europe
Segment Reporting Information [Line Items]
Revenue from contracts with customers	$ 3,328	$ 3,299