INCOME TAXES (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating Loss Carryforwards [Line Items]
Deferred tax assets, operating lease liabilities		$ 176.7	$ 111.5
Deferred tax liabilities, ROU assets		176.7	108.1
State net operating loss carryforwards		75.0	67.7
Interest and penalties recognized as income tax expense (benefit)		0.2	0.0	$ 0.0
Balance of accrued interest and penalties included in liability for unrecognized income tax benefits		0.8	0.3	0.3
Unrecognized income tax benefits that would affect the effective tax rate if recognized		$ 10.3	6.6	$ 5.3
Income tax benefit recognition threshold more likely than not		50.00%
Other Accounts And Notes Receivable [Member]
Operating Loss Carryforwards [Line Items]
Income tax receivables		$ 5.0	5.3
Other Current Assets [Member]
Operating Loss Carryforwards [Line Items]
Income tax receivables		0.6	$ 0.9
Alabama [Member]
Operating Loss Carryforwards [Line Items]
State net operating loss carryforwards		63.2
Increase in valuation allowance	$ 13.7
Alabama [Member] | State [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards, valuation allowance		$ 42.9
Alabama [Member] | State [Member] | Earliest Tax Year [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards expiration year		2023
Alabama [Member] | State [Member] | Latest Tax Year [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards expiration year		2029