v3.26.1
Debt - Narrative (Details)
$ in Millions
1 Months Ended 3 Months Ended 6 Months Ended 12 Months Ended
Jun. 30, 2026
USD ($)
Mar. 31, 2026
USD ($)
Jan. 31, 2026
USD ($)
Jun. 30, 2026
USD ($)
Jun. 30, 2025
USD ($)
Jun. 30, 2026
USD ($)
Jun. 30, 2025
USD ($)
Dec. 31, 2025
USD ($)
Debt Instrument [Line Items]                
Loss on extinguishment of debt           $ 27.7 $ 0.0  
Interest expense       $ 53.8 $ 84.1 139.5 149.7  
Amortization of capitalized discounts and deferred financing fees       3.5 $ 3.7 8.2 7.1  
Debt, fair value $ 3,068.0     3,068.0   3,068.0    
Letter of Credit                
Debt Instrument [Line Items]                
Maximum borrowing capacity 12.9     12.9   12.9   $ 12.9
Madison IAQ LLC                
Debt Instrument [Line Items]                
Letters of credit outstanding 5.7     5.7   5.7   5.7
Senior notes                
Debt Instrument [Line Items]                
Long-term debt, gross $ 1,035.0     $ 1,035.0   $ 1,035.0   1,035.0
Interest rate 5.90%     5.90%   5.90%    
Senior secured notes                
Debt Instrument [Line Items]                
Long-term debt, gross $ 700.0     $ 700.0   $ 700.0   $ 700.0
Interest rate 4.10%     4.10%   4.10%    
Mortgage payable                
Debt Instrument [Line Items]                
Basis spread on variable interest rate               3.83%
Repayment of debt     $ 0.6          
Long-term debt, gross $ 0.0     $ 0.0   $ 0.0   $ 0.6
Credit Agreement | Line of Credit                
Debt Instrument [Line Items]                
Weighted average interest rate for borrowings oustanding 5.50%     5.50%   5.50%   6.70%
Unused commitment fee, percentage   0.25%            
Long-term debt, gross $ 1,345.6     $ 1,345.6   $ 1,345.6   $ 3,977.7
Credit Agreement | Line of Credit | Possible Reduction After September 30, 2026                
Debt Instrument [Line Items]                
Unused commitment fee, percentage   0.05%            
Credit Agreement | Line of Credit | Revolving Credit Facility                
Debt Instrument [Line Items]                
Repayment of line of credit           0.0 0.0  
Proceeds from line of credit           $ 0.0 $ 0.0  
Credit Agreement | Line of Credit | Madison IAQ LLC                
Debt Instrument [Line Items]                
Repayment of line of credit       2,425.7        
Loss on extinguishment of debt       $ 26.2        
2026 Incremental Revolving Facility | Line of Credit | Madison IAQ LLC                
Debt Instrument [Line Items]                
Loss on extinguishment of debt $ 1.5              
Maximum borrowing capacity   $ 1,300.0            
Capitalization of lender fee   4.9            
Total deferred costs   $ 5.7            
2026 Incremental Revolving Facility | Line of Credit | Madison IAQ LLC | SOFR                
Debt Instrument [Line Items]                
Decrease in variable rate 0.0100              
Basis spread on variable interest rate 1.75%              
2026 Incremental Revolving Facility | Line of Credit | Madison IAQ LLC | Base Rate                
Debt Instrument [Line Items]                
Decrease in variable rate 0.0100              
Basis spread on variable interest rate 0.75%              
Incremental Term Loan | Line of Credit | Madison IAQ LLC                
Debt Instrument [Line Items]                
Repayment of line of credit $ 200.0