v3.19.3

DESCRIPTION OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019 USD ($) customer	Sep. 30, 2018 customer	Sep. 30, 2019 USD ($) customer third_party_processor	Sep. 30, 2018 customer	Dec. 31, 2018 USD ($) third_party_processor	Jan. 01, 2019 USD ($)
Concentration Risk [Line Items]
Operating lease right-of-use assets	$ 108,670		$ 108,670
Operating lease liability	132,236		132,236
Derecognition of build-to-suit lease asset	0		0		$ (149,000)
Derecognition of build-to-suit lease liability	$ 0		$ 0		$ (149,000)
Total Net Revenue | Customer Concentration Risk
Concentration Risk [Line Items]
Number of customers accounting for greater than 10% of total net revenue | customer	0	0	0	0
Settlements Receivable | Credit Concentration Risk
Concentration Risk [Line Items]
Number of third party processors | third_party_processor			3		3
Settlements Receivable | Credit Concentration Risk | Third Party Processor One
Concentration Risk [Line Items]
Concentration risk, settlements receivable			46.00%		45.00%
Settlements Receivable | Credit Concentration Risk | Third Party Processor Two
Concentration Risk [Line Items]
Concentration risk, settlements receivable			34.00%		33.00%
Settlements Receivable | Credit Concentration Risk | Third Party Processor Three
Concentration Risk [Line Items]
Concentration risk, settlements receivable			9.00%		9.00%
Minimum
Concentration Risk [Line Items]
Settlements receivable period			1 day
Maximum
Concentration Risk [Line Items]
Settlements receivable period			2 days
Accounting Standards Update 2016-02
Concentration Risk [Line Items]
Operating lease right-of-use assets						$ 112,000
Operating lease liability						135,600
Derecognition of build-to-suit lease asset						149,000
Derecognition of build-to-suit lease liability						$ 149,000

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