EQUITY-BASED COMPENSATION - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	May 31, 2021	Sep. 30, 2020	May 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Income tax (expense) benefits related to equity-based compensation	$ 1,078	$ 1,189
Granted, weighted average grant date fair value (in USD per share)	$ 11.04
Unrecognized compensation expense related to unvested options at end of period	$ 18,211
Period for recognition of unrecognized compensation cost	2 years 1 month 20 days
Fair value of stock options that vested	$ 6,395
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Period for recognition of unrecognized compensation cost	2 years 11 months 19 days
Cost not yet recognized, amount	$ 12,240
Vested in period, fair value	$ 698
2018 Equity Incentive Award Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grant under the plan (in shares)	2,433,717				3,500,000
Additional Class A common shares added at the beginning of calendar year as percentage of common stock outstanding at end of previous year (percent)					4.00%
2020 Equity Incentive Award Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grant under the plan (in shares)	1,230,668		3,000,000	1,500,000