Related Party Transactions (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019	Jun. 25, 2018
Related Party Transaction [Line Items]
Percent of tax benefits payable to continuing equity owners					85.00%
Axia Tech | Affiliated Entity
Related Party Transaction [Line Items]
Net revenue from related party	$ 22	$ 20	$ 44	$ 38
i3Verticals, LLC | Affiliated Entity
Related Party Transaction [Line Items]
Ownership interest in Axia Tech (percent)	2.00%		2.00%
Continuing Equity Owner | Class B Common Stock
Related Party Transaction [Line Items]
Tax benefits due to Continuing Equity Owners	$ 25,799		$ 25,799
Chief Executive Officer | Affiliated Entity
Related Party Transaction [Line Items]
Ownership interest in Axia Tech (percent)	10.50%		10.50%
Chief Financial Officer | Affiliated Entity
Related Party Transaction [Line Items]
Ownership interest in Axia Tech (percent)	0.40%		0.40%