Annual report pursuant to Section 13 and 15(d)

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

v3.22.4
Business Combinations and Acquisitions - Schedule of Business Acquisition, Pro Forma Information (Details) - USD ($)
$ in Millions
 2 Months Ended 4 Months Ended 12 Months Ended
Dec. 01, 2021
Oct. 20, 2021
Dec. 31, 2021
Oct. 19, 2021
Dec. 31, 2022
Jun. 30, 2021
Jun. 30, 2020
Business Acquisition [Line Items]              
Goodwill   $ 0.0 $ 1,662.6 $ 677.4 $ 1,418.0 $ 681.5 $ 522.6
Payments to Acquire Businesses, Net of Cash Acquired     58.6 0.9 $ 6.6 290.1 55.7
Interest Rate Swap Cap Agreement              
Business Acquisition [Line Items]              
Other long-term liabilities $ (9.0)            
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          
Business Combination, Consideration Transferred   (2,632.3)          
Less: cash acquired   (101.9)          
Payments to Acquire Businesses, 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           670.9 598.7
Net loss           (142.9) (239.2)
Net loss attributable to Mirion TopCo stockholders           $ (127.9) $ (158.3)
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)            
Business Combination, Consideration Transferred (55.1)            
Less: cash acquired (1.0)            
Payments to Acquire Businesses, 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