GOODWILL AND OTHER INTANGIBLE ASSETS - Schedule of Intangible Assets (Details) - USD ($) $ in Thousands		3 Months Ended	12 Months Ended
	May 09, 2016	Sep. 30, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Sep. 15, 2017
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Amortization Expense, Total			$ 35,292
Gain (Loss) on Disposition of Intangible Assets			0	$ 0	$ 17,149
Proceeds from sale of intangible assets			0	1,500	18,333
Gross Carrying Value			100,738	107,570
Accumulated Amortization			65,446	62,169
Net Carrying Value			35,292	45,401
Disposition of Intangible Assets, Gross Consideration Received	$ 16,000
Professional Fees			700
Amortization of acquired intangible assets			14,355	14,498	$ 23,032
Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value			16,200	16,200
Accumulated Amortization			16,200	11,700
Net Carrying Value			0	4,500
Merchant relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value			22,193	21,554
Accumulated Amortization			8,268	4,105
Net Carrying Value			13,925	17,449
Trade names
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value			9,558	9,476
Accumulated Amortization			7,369	6,799
Net Carrying Value			2,189	2,677
Developed technology
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value			3,651	13,825
Accumulated Amortization			2,685	13,485
Net Carrying Value			966	340
Patents
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value			23,021	20,508
Accumulated Amortization			18,167	16,451
Net Carrying Value			4,854	4,057
Other Intangible Assets
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value			26,115	26,007
Accumulated Amortization			12,757	9,629
Net Carrying Value			$ 13,358	$ 16,378
OrderUp Intangible [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Gain (Loss) on Disposition of Intangible Assets		$ 17,100
Proceeds from sale of intangible assets		19,800
Disposition of Intangible Assets, Gross Consideration Received		20,000
Professional Fees		$ 200
Other Intangible Assets, Net						$ 2,700
Minimum
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets, useful life			1 year
Maximum
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets, useful life			10 years