Income Taxes - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Tax Credit Carryforward [Line Items]
Income tax expense (benefit)	$ 5.6	$ (0.8)	$ (22.4)
Proceeds from Income Tax Refunds	0.0	11.3	24.6
Income taxes receivable (1)	27.1	34.4
Deferred tax assets, gross	188.2	181.1
Valuation allowance	185.1	178.5
Net operating loss carryforwards and credits - state and local	82.0	90.3
Total interest and penalties	1.2	(1.0)	$ (0.1)
Accruals for interest and penalties	3.4	2.2
Liability for selected tax items	8.7	8.7
U.S.
Tax Credit Carryforward [Line Items]
Deferred tax assets, gross	183.9	177.5
Valuation allowance	183.9	$ 177.5
U.S. NOL carryforwards	504.8
Net operating loss carryforwards and credits - state and local	82.0
USVI
Tax Credit Carryforward [Line Items]
Proceeds from Income Tax Refunds	7.1
Income taxes receivable (1)	12.9
Expected carry back of net operating loss	334.5
India and Philippines Subsidiary
Tax Credit Carryforward [Line Items]
Deferred tax liability	0.4
CARES Act Claims
Tax Credit Carryforward [Line Items]
Income tax expense (benefit)	(12.6)
SEC Schedule, 12-09, Valuation Allowance, Operating Loss Carryforward | U.S.
Tax Credit Carryforward [Line Items]
Valuation allowance on deferred tax assets	106.0
Capital Loss Carryforward | U.S.
Tax Credit Carryforward [Line Items]
Capital loss carryforwards	0.1
Disallowed Interest Carryforward
Tax Credit Carryforward [Line Items]
Tax Credit Carryforward, Amount	$ 498.7