Goodwill and Other Identifiable Intangible Assets - Summary of Changes in Goodwill and Identifiable Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022
Goodwill [Roll Forward]
Net balance - beginning of period			$ 378,588
Acquisition			18,480
Other adjustments			401
Net balance - end of period	$ 397,469		397,469
Intangible Assets [Abstract]
Net balance - beginning of period			306,471
Acquisitions			8,826
Accumulated amortization	(3,300)	$ (2,600)	(6,586)	$ (2,600)
Net balance - end of period	308,711		308,711
Developed Technologies
Intangible Assets [Abstract]
Net balance - beginning of period			14,274
Acquisitions			0
Accumulated amortization			(773)
Net balance - end of period	13,501		13,501
Customer Relationships
Intangible Assets [Abstract]
Net balance - beginning of period			101,230
Acquisitions			0
Accumulated amortization			(5,374)
Net balance - end of period	95,856		95,856
Domain Names
Intangible Assets [Abstract]
Net balance - beginning of period			1,970
Acquisitions			0
Accumulated amortization			(208)
Net balance - end of period	1,762		1,762
Internally Developed Software
Intangible Assets [Abstract]
Net balance - beginning of period			2,218
Acquisitions			26
Accumulated amortization			(231)
Net balance - end of period	2,013		2,013
Trade Names
Intangible Assets [Abstract]
Net balance - beginning of period			186,779
Acquisitions			8,800
Net balance - end of period	$ 195,579		$ 195,579