Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Cash flows from operating activities:
Net loss (income)	$ (7,823)	$ 518
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	8,876	7,453
Equity-based compensation	817	0
Provision (benefit) for doubtful accounts	33	(33)
Amortization of deferred financing costs	835	329
Loss on disposal of assets	5	43
Benefit for deferred income taxes	(468)	0
Non-cash change in fair value of warrant liability	8,487	(58)
Increase in non-cash contingent consideration expense from original estimate	3,280	177
Changes in operating assets:
Accounts receivable	2,205	745
Prepaid expenses and other current assets	1,433	37
Restricted cash	348	(600)
Other assets	(2,994)	31
Changes in operating liabilities:
Accounts payable	724	(72)
Accrued expenses and other current liabilities	2,936	178
Deferred revenue	(3,033)	(2,096)
Other long-term liabilities	160	69
Contingent consideration paid in excess of original estimates	(814)	(783)
Net cash provided by operating activities	15,007	5,938
Cash flows from investing activities:
Expenditures for property and equipment	(1,309)	(545)
Expenditures for capitalized software	(760)	(780)
Purchases of merchant portfolios and residual buyouts	(1,207)	(1,202)
Acquisitions of businesses, net of cash acquired	(26,862)	(5,175)
Acquisition of other intangibles	(818)	(8)
Net cash used in investing activities	(30,956)	(7,710)
Cash flows from financing activities:
Proceeds from revolving credit facility	19,250	13,000
Payments of revolving credit facility	(90,850)	(9,000)
Proceeds from notes payable to banks	24,671	0
Payments of notes payable to banks	(3,750)	(4,000)
Payment of notes payable to Mezzanine Lenders	(10,486)	0
Payment of unsecured notes payable to related and unrelated creditors	(5,489)	0
Payment of debt issuance costs	(266)	0
Proceeds from the exercise of Mezzanine Warrants and Junior Subordinated Notes Warrants	270	0
Proceeds from issuance of Class A common stock sold in initial public offering, net of underwriting discounts and offering costs	89,729	0
Payments for Common Units in i3 Verticals, LLC from selling shareholder	(4,635)	0
Payment of equity issuance costs for 2017 Class A unit issuance	0	(4)
Cash paid for contingent consideration	(977)	(517)
Required distributions to members for tax obligations	0	(931)
Net cash provided by (used in) financing activities	17,467	(1,452)
Net increase (decrease) in cash and cash equivalents	1,518	(3,224)
Cash and cash equivalents, beginning of period	955	3,776
Cash and cash equivalents, end of period	2,473	552
Supplemental disclosure of cash flow information:
Cash paid for interest	8,961	4,569
Cash paid for income taxes	137	1,586
Supplemental disclosure of non-cash investing and financing activities:
Common Units issued as part of acquisitions' purchase consideration (Note 3)	104	0
Acquisition date fair value of contingent consideration in connection with business combinations	2,084	1,221
Replacement of 2016 Senior Secured Credit Facility with Senior Secured Credit Facility	87,525	0
Mezzanine Notes net settled with Mezzanine Warrant exercises	14	0
Unsecured notes payable to related and unrelated creditors net settled with Junior Subordinated Notes Warrants	2,565	0
Settlement of warrant liability with equity as a result of Mezzanine Warrant exercise	9,253	0
Debt issuance costs financed with proceeds from Senior Secured Credit Facility	904	0
Conversion of notes payable to related and unrelated creditors to Class A common stock	8,054	0
Increase in accrued equity issuance costs	760	0
Redeemable Class A
Supplemental disclosure of non-cash investing and financing activities:
Preferred return on Class A Units and Redeemable Class A Units	552	521
Class A
Cash flows from operating activities:
Net loss (income)	(138)
Supplemental disclosure of non-cash investing and financing activities:
Preferred return on Class A Units and Redeemable Class A Units	$ 2,522	$ 1,483