Fair Value Measurements - Summary of Financial Assets and Liabilities Measured at Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Liabilities:
Contingent Consideration	$ 2,600	$ 15,300	$ 9,200
Reported Value Measurement
Assets:
Investment in Equity Securities	326	772
Liabilities:
Contingent Consideration	21,181	37,402
Level 1 | Reported Value Measurement
Assets:
Investment in Equity Securities	326	772
Liabilities:
Contingent Consideration	0	0
Level 2 | Reported Value Measurement
Assets:
Investment in Equity Securities	0	0
Liabilities:
Contingent Consideration	0	0
Level 3 | Reported Value Measurement
Assets:
Investment in Equity Securities	0	0
Liabilities:
Contingent Consideration	$ 21,181	$ 37,402