Summary of Significant Accounting Policies (Details)		12 Months Ended
	Oct. 01, 2020 USD ($)	Sep. 30, 2020 USD ($) reportable_unit	Sep. 30, 2019 USD ($)		Sep. 30, 2018 USD ($)		Oct. 01, 2019 USD ($)
Concentration Risk [Line Items]
Allowance for doubtful accounts		$ 310,000	$ 232,000
Inventories		1,309,000	1,294,000
Impairment charges		$ 0	0		$ 0
Estimated useful life		3 years
Notes receivable, fair value disclosure		$ 1,195,000	195,000
Revenue from acquisitions		1,275,000
Net income		327,000
Goodwill impairment		$ 0	0		0
Number of reporting units | reportable_unit		5
Amortization expense of intangible assets		$ 12,414,000	12,394,000		9,341,000
Impairment of intangible assets, excluding goodwill		0	0		0
Capitalized contract cost, gross		3,140,000
Advertising expense		1,813,000	1,443,000		926,000
Equity-based compensation expense		10,452,000	6,124,000		1,567,000
Benefit from income taxes		$ 2,795,000	177,000		(337,000)
Accounting Standards Update [Extensible List]		us-gaap:AccountingStandardsUpdate201409Member
Cumulative increase to equity		$ 240,168,000	142,441,000		112,198,000
Accumulated earnings		(2,023,000)	(2,309,000)
Non-controlling interest		84,590,000	62,368,000
Interchange and network fees		0	242,867,000	[1]	214,543,000	[1]
Subsequent Event
Concentration Risk [Line Items]
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201602Member
Presentation without adoption of ASC 606
Concentration Risk [Line Items]
Accumulated earnings		(2,895,000)
Non-controlling interest		83,846,000
Interchange and network fees		244,097,000
Operating Expense
Concentration Risk [Line Items]
Interchange and network fees			242,867,000		$ 214,543,000
Cumulative Effect, Period of Adoption, Adjustment
Concentration Risk [Line Items]
Cumulative increase to equity			1,345,000
Accumulated earnings							$ 705,000
Non-controlling interest							$ 640,000
Cumulative Effect, Period of Adoption, Adjustment | Subsequent Event | Forecast
Concentration Risk [Line Items]
Right-of-Use asset	$ 9,093,000
Lease liability	$ 9,760,000
Class B Common Stock
Concentration Risk [Line Items]
Reduction in the benefit from income taxes		235,000
Increase to net loss		3,728,000
Reduction in company's net loss		3,493,000
Intangible Assets, Amortization Period
Concentration Risk [Line Items]
Amortization expense of intangible assets		398,000	$ 1,290,000
Change in Accounting Method Accounted for as Change in Estimate
Concentration Risk [Line Items]
Change in valuation allowance for deferred tax assets		2,668,000
Benefit from income taxes		$ (2,668,000)

[1] Effective October 1, 2019, the Company's revenues are presented net of interchange and network fees in accordance with Accounting Standards Codification Topic 606, Revenue from Contracts with Customers. See Note 2 to our consolidated financial statements for a description of the recently adopted accounting pronouncement.