SEGMENTS - Adjusted Contribution Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Segment Reporting [Abstract]
Adjusted contribution	$ 35,125	$ 29,630	$ 67,900	$ 53,971
Deferred implementation costs	0	730	0	1,612
Delivery costs	8,162	5,748	14,695	9,686
Sales and marketing expense	21,983	17,063	39,631	30,265
Research and development expense	13,581	8,934	25,872	15,152
General and administration expense	20,984	16,888	41,409	29,063
Acquisition and integration costs (benefit)	2,197	14,182	(2,401)	21,212
Change in fair value of contingent consideration	(2,968)	1,480	(68,018)	1,480
Depreciation and amortization expense	10,356	8,833	20,227	11,898
Total other expense	5,417	3,078	8,034	5,804
Loss before income taxes	$ (127,736)	$ (47,306)	$ (94,698)	$ (72,201)