Long Term Debt - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended	3 Months Ended		9 Months Ended
	May 26, 2023	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	May 01, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Legal and other fees		$ 0.5		$ 0.5
Multiple consolidated interest expense under sub condition two of condition two under dividend restriction				1.75
Interest rate		4.50%		4.50%
Restricted payments available amount		$ 448.2		$ 448.2
Minimum
Debt Instrument [Line Items]
Net Total Leverage Ratio				1.00%
Net Total Leverage Ratio Maximum				1.00%
Net Total Leverage Ratio Minimum				1.00%
Maximum
Debt Instrument [Line Items]
Net Total Leverage Ratio				2.75%
Net Total Leverage Ratio Maximum				5.00%
Net Total Leverage Ratio Minimum				2.75%
5.875% Senior Notes
Debt Instrument [Line Items]
Interest rate	5.875%
5.250% Senior Notes
Debt Instrument [Line Items]
Interest rate	5.25%
4.50 % Convertible Senior Notes
Debt Instrument [Line Items]
Interest rate		4.50%		4.50%
8.750 % Senior Notes
Debt Instrument [Line Items]
Aggregate principal amount of add-on to Senior Notes						$ 100.0
Debt instrument accrued interest				$ 106.6
Debt total						$ 3.4
Deferred Debt Issuance Cost, Writeoff				1.2
Premium paid on the redemption of bond				2.2
Interest rate	8.75%					8.75%
Remaining principal amount of optional redemption				150.0
unamortized debt issuance costs				$ 1.2
Amended Senior Secured Credit Facility [Member] | Minimum
Debt Instrument [Line Items]
Senior Secured Leverage Ratio Required				1.00%
Amended Senior Secured Credit Facility [Member] | Maximum
Debt Instrument [Line Items]
Senior Secured Leverage Ratio Required				3.50%
Revolving Credit Facility [Member] | Amended Senior Secured Credit Facility [Member] | Minimum
Debt Instrument [Line Items]
Senior Secured Leverage Ratio Required				0.30%
Revolving Credit Facility [Member] | Amended Senior Secured Credit Facility [Member] | Maximum
Debt Instrument [Line Items]
Senior Secured Leverage Ratio Required				1.00%
CUSA [Member]
Debt Instrument [Line Items]
Total leverage ratio, percentage				0.25%
Repayments of long-term debt				$ (8.6)	$ (14.0)
Proceeds, net from long term borrowing				$ 632.7
Average interest rate on outstanding borrowings		6.90%		6.90%
Debt issuance costs		$ 29.1		$ 29.1			$ 22.9
Debt instrument, maturity date				May 24, 2030
Loss on debt extinguishment and refinancing		0.0	$ 0.0	$ 10.7	$ 0.0
Fair value of long-term debt		1,873.3		$ 1,873.3			$ 1,771.3
CUSA [Member] | Minimum
Debt Instrument [Line Items]
Percentage of variable margin rate added to Eurodollar rate				0.20%
CUSA [Member] | Maximum
Debt Instrument [Line Items]
Percentage of variable margin rate added to Eurodollar rate				0.375%
CUSA [Member] | Senior Secured Credit Facility
Debt Instrument [Line Items]
Aggregate principal amount of add-on to Senior Notes	$ 775.0
CUSA [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Revolving credit line, maturity date	May 26, 2028
Term Loan Credit facility
Debt Instrument [Line Items]
PercentageOfVariableRateAddedToSecuredOvernightFinancingRate				0.50%
Percentage of variable margin rate added to Eurodollar rate				2.75%
Term Loan Credit facility | Minimum
Debt Instrument [Line Items]
Total leverage ratio, percentage				1.00%
Term Loan Credit facility | Maximum
Debt Instrument [Line Items]
Net Total Leverage Ratio				2.22%
Term Loan Credit facility | Senior Secured Credit Facility
Debt Instrument [Line Items]
Debt instrument description of interest				SOFR for a period of 1, 3, or 6 months (depending upon the Interest Period (as defined in the Credit Agreement) chosen by CUSA) (the "Term SOFR Rate"), subject to a floor of 0.50% per annum, plus an applicable margin of 3.75% per annum,
Term Loan Credit facility | 5.250% Senior Notes
Debt Instrument [Line Items]
Interest rate	5.25%
Term Loan Credit facility | Amended Senior Secured Credit Facility [Member]
Debt Instrument [Line Items]
Percentage of variable margin rate added to Eurodollar rate				3.75%
Percentage Of Variable Rate Added To Federal Reserve Bank Effective Rate				1.00%
Percentage Of Variable Rate Added To Alternate Base Rate				1.00%
Term Loan Credit facility | CUSA [Member]
Debt Instrument [Line Items]
Original issue discount				$ 9.8
Debt issuance costs capitalized		7.5		7.5
Lender fees paid on debt extinguishment				2.1
Unamortized debt issuance costs		4.7		4.7
Repayments of long-term debt				(628.3)
Debt issuance costs		10.1		$ 10.1
Term Loan Credit facility | CUSA [Member] | Senior Secured Credit Facility
Debt Instrument [Line Items]
Aggregate principal amount of add-on to Senior Notes	$ 650.0
Quarterly principal payments due	$ 1.6
Last quarterly payment date	Mar. 31, 2030
Final principal payment due date	May 24, 2030
Revolving Credit Line
Debt Instrument [Line Items]
Percentage Of Variable Rate Added To Alternate Base Rate				1.00%
Revolving Credit Line | Amended Senior Secured Credit Facility [Member]
Debt Instrument [Line Items]
Amount outstanding under the revolving credit line		0.0		$ 0.0
Long-term Line of Credit, Total		$ 0.0		$ 0.0
Percentage of variable margin rate added to Eurodollar rate				3.25%
Percentage Of Variable Rate Added To Alternate Base Rate				1.50%
Revolving Credit Line | Amended Senior Secured Credit Facility [Member] | Minimum
Debt Instrument [Line Items]
PercentageOfVariableRateAddedToSecuredOvernightFinancingRate				3.00%
Percentage Of Variable Rate Added To Alternate Base Rate				2.00%
Revolving Credit Line | Amended Senior Secured Credit Facility [Member] | Maximum
Debt Instrument [Line Items]
PercentageOfVariableRateAddedToSecuredOvernightFinancingRate				3.50%
Percentage Of Variable Rate Added To Alternate Base Rate				2.50%
Revolving Credit Line | CUSA [Member] | Senior Secured Credit Facility
Debt Instrument [Line Items]
Aggregate principal amount of add-on to Senior Notes	$ 125.0