Financial Instruments and Fair Value Measurements - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 26, 2025	Sep. 27, 2024	Sep. 26, 2025	Sep. 27, 2024	Dec. 27, 2024	Apr. 23, 2024	Mar. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Unrealized gain (loss)	$ 0.4	$ (1.3)	$ (2.6)	$ 1.4
Derivative, notional value							$ 860.0
Derivative, interest rate cap, premium							$ 20.0
Cap interest rate, percent							3.84%
Proceeds from life insurance contracts			$ 14.0	0.0
8.50% Senior Secured Notes due April 2031
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Interest rate percentage	8.50%		8.50%			8.50%
Level 1 | Indemnification Agreement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Restricted cash, carrying value	$ 155.1		$ 155.1		$ 63.1
Level 3 | Other current and non-current assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash surrender value of life insurance	30.9		30.9		43.7
Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Derivative liability	0.0		0.0		0.0
Contingent consideration liabilities	43.8		43.8		17.5
Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Contingent consideration liabilities	0.0		0.0		0.0
Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Contingent consideration liabilities	43.8		43.8		17.5
Recurring | Level 3 | Auxilium
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Contingent consideration liabilities	23.5		23.5		$ 0.0
Contingent consideration, current liabilities	2.9		2.9
Interest Rate Cap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Unrealized gain (loss) on derivatives	$ (1.4)	(9.9)	$ (4.4)	(8.6)
Embedded Derivative Financial Instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Unrealized gain (loss) on derivatives		$ (8.0)		$ (2.7)