SEGMENTS - Adjusted Contribution Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Segment Reporting [Abstract]
Adjusted Contribution	$ 158,626	$ 143,035	$ 129,628
Deferred implementation costs	0	0	3,785
Delivery costs	28,248	30,403	22,503
Sales and marketing expense	57,425	74,745	65,996
Research and development expense	51,352	54,435	38,104
General and administration expense	58,810	81,446	66,222
Depreciation and amortization expense	26,460	37,544	29,871
Total non-operating (income) expense	(968)	8,932	13,830
Acquisition, integration and divestiture (benefits) costs	(6,313)	(2,874)	24,372
Loss on divestiture	6,550	0	0
Loss before income taxes	(134,702)	(466,710)	(136,429)
Income tax benefit	0	(1,446)	(7,864)
Change in fair value of contingent consideration	1,246	(128,174)	1,374
Impairment of goodwill and intangible assets	$ 70,518	$ 453,288	$ 0