Revenue - Summary (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenue
Revenue	$ 94,283	$ 122,517	$ 205,452	$ 234,035
Direct
Revenue
Revenue	52,016	75,890	118,752	144,086
Tech-enabled
Revenue
Revenue	35,663	38,471	73,184	73,547
Traditional
Revenue
Revenue	6,604	8,156	13,516	16,402
Americas
Revenue
Revenue	61,952	77,656	132,824	147,621
Americas | Direct
Revenue
Revenue	26,310	40,109	61,987	75,221
Americas | Tech-enabled
Revenue
Revenue	29,038	29,391	57,321	55,998
Americas | Traditional
Revenue
Revenue	6,604	8,156	13,516	16,402
Europe
Revenue
Revenue	32,331	44,861	72,628	86,414
Europe | Direct
Revenue
Revenue	25,706	35,781	56,765	68,865
Europe | Tech-enabled
Revenue
Revenue	$ 6,625	$ 9,080	$ 15,863	$ 17,549