Annual report pursuant to Section 13 and 15(d)

Business Combinations and Acquisitions - Schedule of Business Acquisition, Pro Forma Information (Details)

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Business Combinations and Acquisitions - Schedule of Business Acquisition, Pro Forma Information (Details) - USD ($)
$ in Millions
 2 Months Ended 4 Months Ended 10 Months Ended 12 Months Ended
Dec. 01, 2021
Oct. 20, 2021
Dec. 18, 2020
Sep. 01, 2020
Dec. 31, 2021
Oct. 19, 2021
Jun. 30, 2021
Dec. 31, 2023
Dec. 31, 2022
Jun. 30, 2021
Business Acquisition [Line Items]                    
Goodwill         $ 1,662.6     $ 1,447.6 $ 1,418.0  
GAAP purchase consideration, net of cash acquired         58.6 $ 0.9   $ 31.4 $ 6.6 $ 290.1
Interest Rate Swap Cap Agreement                    
Business Acquisition [Line Items]                    
Other long-term liabilities $ (9.0)                  
Trade names                    
Business Acquisition [Line Items]                    
Original Average Life in Years   10 years 7 years 7 years            
Mirion                    
Business Acquisition [Line Items]                    
Total revenues         154.1 168.0       611.6
Net loss         (5.2) (56.3)       (192.1)
Net loss attributable to Mirion TopCo stockholders         $ (3.6) $ (54.0)       (184.2)
Goodwill   $ 1,642.9                
Total amortizable intangible assets   821.0                
Cash   101.9                
Accounts receivable   114.3                
Inventory   144.6                
Property, Plant and Equipment   126.4                
Current lease liability   (8.8)                
Other long-term liabilities   (241.4)                
Net tangible assets acquired   168.4                
Purchase consideration   (2,632.3)                
Less: cash acquired   (101.9)                
GAAP purchase consideration, net of cash acquired   2,530.4                
Mirion | Developed technology                    
Business Acquisition [Line Items]                    
Total amortizable intangible assets   234.6                
Mirion | Customer relationships                    
Business Acquisition [Line Items]                    
Total amortizable intangible assets   338.8                
Mirion | Trade names                    
Business Acquisition [Line Items]                    
Total amortizable intangible assets   100.5                
Mirion | Backlog and other                    
Business Acquisition [Line Items]                    
Total amortizable intangible assets   81.5                
Mirion | Medical                    
Business Acquisition [Line Items]                    
Goodwill   680.4                
Total amortizable intangible assets   330.5                
Cash   7.8                
Accounts receivable   44.0                
Inventory   25.1                
Property, Plant and Equipment   52.6                
Current lease liability   (4.1)                
Other long-term liabilities   (70.0)                
Net tangible assets acquired   23.2                
Mirion | Medical | Developed technology                    
Business Acquisition [Line Items]                    
Total amortizable intangible assets   66.3                
Mirion | Medical | Customer relationships                    
Business Acquisition [Line Items]                    
Total amortizable intangible assets   152.7                
Mirion | Medical | Trade names                    
Business Acquisition [Line Items]                    
Total amortizable intangible assets   36.8                
Mirion | Medical | Backlog and other                    
Business Acquisition [Line Items]                    
Total amortizable intangible assets   $ 17.7                
Biodex and SNC                    
Business Acquisition [Line Items]                    
Total revenues                   670.9
Net loss                   (142.9)
Net loss attributable to Mirion TopCo stockholders                   $ (127.9)
CIRS | Developed technology                    
Business Acquisition [Line Items]                    
Original Average Life in Years 5 years                  
CIRS | Customer relationships                    
Business Acquisition [Line Items]                    
Original Average Life in Years 7 years                  
CIRS | Trade names                    
Business Acquisition [Line Items]                    
Original Average Life in Years 3 years                  
CIRS | Backlog and other                    
Business Acquisition [Line Items]                    
Original Average Life in Years 2 years                  
CIRS | Medical                    
Business Acquisition [Line Items]                    
Goodwill $ 34.0                  
Total amortizable intangible assets 21.8                  
Cash 1.0                  
Accounts receivable 1.6                  
Inventory 2.0                  
Property, Plant and Equipment 0.4                  
Operating ROU assets 3.8                  
Current lease liability (0.5)                  
Net tangible assets acquired (1.7)                  
Purchase consideration (55.1)                  
Less: cash acquired (1.0)                  
GAAP purchase consideration, net of cash acquired 54.1                  
Acquiree revenue post acquisition through the period ended December 31, 2021 1.5                  
Acquiree income (loss) from operations post acquisition through the period ended December 31, 2021 (0.1)                  
CIRS | Medical | Developed technology                    
Business Acquisition [Line Items]                    
Total amortizable intangible assets 19.2                  
CIRS | Medical | Customer relationships                    
Business Acquisition [Line Items]                    
Total amortizable intangible assets 1.6                  
CIRS | Medical | Trade names                    
Business Acquisition [Line Items]                    
Total amortizable intangible assets 0.4                  
CIRS | Medical | Backlog and other                    
Business Acquisition [Line Items]                    
Total amortizable intangible assets $ 0.6                  
Biodex | Medical                    
Business Acquisition [Line Items]                    
Goodwill       $ 11.1            
Total amortizable intangible assets       6.6            
Cash       4.1            
Accounts receivable       4.0            
Inventory       6.4            
Property, Plant and Equipment       1.0            
Other long-term liabilities       0.0            
Net tangible assets acquired       13.3            
Purchase consideration             $ (31.0)      
Less: cash acquired             (4.1)      
GAAP purchase consideration, net of cash acquired             26.9      
Acquiree revenue post acquisition through the period ended December 31, 2021             32.6      
Acquiree income (loss) from operations post acquisition through the period ended December 31, 2021             $ 0.7      
Biodex | Medical | Developed technology                    
Business Acquisition [Line Items]                    
Total amortizable intangible assets       2.6            
Biodex | Medical | Customer relationships                    
Business Acquisition [Line Items]                    
Total amortizable intangible assets       2.3            
Biodex | Medical | Trade names                    
Business Acquisition [Line Items]                    
Total amortizable intangible assets       $ 1.4