Goodwill and Intangible Assets - Summary of Changes in Goodwill and Identifiable Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Goodwill [Roll Forward]
Net balance - beginning of period	$ 336,602	$ 336,602
Acquisition	0	0
Impairment	(77,648)	0	$ (57,700)
Net balance - end of period	258,954	336,602	336,602
Indefinite-Lived Intangible Assets [Roll Forward]
Impairment of intangible assets, indefinite-lived	(23,900)	0	(43,000)
Restructuring and impairment	77,648	0	57,700
Impairment of intangible assets, finite-lived	44,300	0	46,700
Impairment recorded	$ 68,196
Impairment, Intangible Asset, Statement of Income or Comprehensive Income [Extensible Enumeration]	Restructuring and impairment
Intangible Assets, Other Adjustments	$ (119)
Finite-Lived Intangible Assets [Roll Forward]
Impairment	(44,300)	0	(46,700)
Amortized expense	(8,066)	(7,842)	(13,400)
Net balance - end of period	4,190
Intangible Assets Disclosure [Roll Forward]
Net balance - beginning of period	205,391	212,324
Acquisition	1,188	909
Impairment recorded	(68,196)
Net balance - end of period	130,198	205,391	212,324
Trade Names
Indefinite-Lived Intangible Assets [Roll Forward]
Net balance - beginning of period	149,921	149,921
Acquisitions	0	0
Impairment of intangible assets, indefinite-lived	(23,913)
Net balance - end of period	126,008	149,921	149,921
Developed Technologies
Indefinite-Lived Intangible Assets [Roll Forward]
Impairment of intangible assets, finite-lived	3,470
Finite-Lived Intangible Assets [Roll Forward]
Net balance - beginning of period	3,964	4,419
Acquisitions	0	0
Impairment	(3,470)
Amortized expense	(494)	(455)
Net balance - end of period	0	3,964	4,419
Customer Relationships
Indefinite-Lived Intangible Assets [Roll Forward]
Impairment of intangible assets, finite-lived	40,813
Finite-Lived Intangible Assets [Roll Forward]
Net balance - beginning of period	46,403	52,114
Acquisitions	0	0
Impairment	(40,813)
Amortized expense	(5,590)	(5,711)
Net balance - end of period	0	46,403	52,114
Domain Names
Indefinite-Lived Intangible Assets [Roll Forward]
Impairment of intangible assets, finite-lived	0
Finite-Lived Intangible Assets, Period Increase (Decrease)	(119)
Finite-Lived Intangible Assets [Roll Forward]
Net balance - beginning of period	1,750	2,387
Acquisitions	0	0
Impairment	0
Amortized expense	(617)	(637)
Net balance - end of period	1,014	1,750	2,387
Internally Developed Software
Indefinite-Lived Intangible Assets [Roll Forward]
Impairment of intangible assets, finite-lived	0
Finite-Lived Intangible Assets [Roll Forward]
Net balance - beginning of period	3,353	3,483
Acquisitions	1,188	909
Impairment	0
Amortized expense	(1,365)	(1,039)	(600)
Net balance - end of period	$ 3,176	$ 3,353	$ 3,483