BASIS OF PRESENTATION - Narrative (Details) $ in Millions	Sep. 30, 2021 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Deferred employer payroll taxes	$ 8.9
Accrued Liabilities
Summary Of Significant Accounting Policies [Line Items]
Deferred employer payroll taxes	4.5
Other Noncurrent Liabilities
Summary Of Significant Accounting Policies [Line Items]
Deferred employer payroll taxes	4.4
Senior Secured Revolving Credit Facility | Line of Credit
Summary Of Significant Accounting Policies [Line Items]
Current borrowing capacity	$ 450.0