SEGMENT INFORMATION - Schedule of Segment Reporting Information by Segment (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenues:
Revenues	$ 125,014	$ 92,356	$ 238,311	$ 189,289
Income (loss) from operations:
Total income from operations of reportable segments	7,405	4,031	11,932	7,590
Depreciation and amortization:
Depreciation and amortization	10,723	10,363	19,793	20,635
Consumer Payments
Revenues:
Revenues	119,625	81,707	228,018	167,738
Commercial Payments
Revenues:
Revenues	4,041	5,654	7,541	12,022
Integrated Partners
Revenues:
Revenues	1,348	4,995	2,752	9,529
Operating Segments
Income (loss) from operations:
Total income from operations of reportable segments	14,634	8,590	27,680	16,874
Operating Segments \| Consumer Payments
Income (loss) from operations:
Total income from operations of reportable segments	14,448	7,270	27,811	14,422
Depreciation and amortization:
Depreciation and amortization	10,297	8,657	18,876	17,240
Operating Segments \| Commercial Payments
Income (loss) from operations:
Total income from operations of reportable segments	21	475	(388)	1,239
Depreciation and amortization:
Depreciation and amortization	73	78	147	154
Operating Segments \| Integrated Partners
Income (loss) from operations:
Total income from operations of reportable segments	165	845	257	1,213
Depreciation and amortization:
Depreciation and amortization	76	1,334	205	2,645
Corporate
Income (loss) from operations:
Total income from operations of reportable segments	(7,229)	(4,559)	(15,748)	(9,284)
Depreciation and amortization:
Depreciation and amortization	$ 277	$ 294	$ 565	$ 596