Significant Non-cash Transactions (Tables)

12 Months Ended

Sep. 30, 2020

Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract]

Schedule of Significant Noncash Transactions

The Company engaged in the following significant non-cash investing and financing activities during the years ended September 30, 2020, 2019, and 2018:

	Year ended September 30,
	2020		2019		2018
Common Units issued as part of acquisitions' purchase consideration (Note 4)	$	—	$	—	$	104
Restricted Class A common stock issued as part of acquisitions' purchase consideration (Note 4)	$	—	$	225	$	550
Acquisition date fair value of contingent consideration in connection with business combinations	$	4,748	$	13,032	$	2,084
Replacement of the 2016 Senior Secured Credit Facility with the 2017 Senior Secured Credit Facility	$	—	$	—	$	87,525
Replacement of the 2017 Senior Secured Credit Facility with the Senior Secured Credit Facility	$	—	$	100,229	$	—
Mezzanine Notes net settled with Mezzanine Warrant exercises	$	—	$	—	$	14
Unsecured notes payable to related and unrelated creditors net settled with Junior Subordinated Notes Warrants	$	—	$	—	$	2,565
Settlement of warrant liability with equity as a result of Mezzanine Warrant exercise	$	—	$	—	$	9,253
Preferred return on Redeemable Class A Units	$	—	$	—	$	552
Preferred return on Class A Units	$	—	$	—	$	2,522
Debt issuance costs financed with proceeds from the 2017 Senior Secured Credit Facility	$	—	$	—	$	904
Debt issuance costs and accrued interest financed with proceeds from the 2019 Senior Secured Credit Facility	$	—	$	1,271	$	—
Conversion of notes payable to related and unrelated creditors to Class A common stock	$	—	$	—	$	8,054