Annual report pursuant to Section 13 and 15(d)

Stock-Based Compensation - Narrative (Details)

v3.24.0.1
Stock-Based Compensation - Narrative (Details)
$ / shares in Units, $ in Millions
 4 Months Ended 12 Months Ended
Oct. 20, 2021
$ / shares
shares
Oct. 19, 2021
shares
Jun. 17, 2021
shares
Oct. 19, 2021
shares
Dec. 31, 2023
USD ($)
installment
$ / shares
shares
Dec. 31, 2022
USD ($)
$ / shares
shares
Jun. 30, 2021
USD ($)
shares
Jan. 01, 2023
shares
Dec. 31, 2021
$ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Profit interests, percent     50.00%            
Share-based compensation arrangement by share-based payment award, vesting, number of Installments | installment         4        
Unrecognized compensation expense | $         $ 2.8        
Expected period for recognition         9 months 18 days        
Common stock, shares outstanding (in shares)         18,750,000        
Profit Interest 1                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Profit interests (in shares)     3,200,000            
Profits interest, threshold price (in dollars per share) | $ / shares $ 12       $ 12 $ 14     $ 16
Profit Interest 2                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Profit interests (in shares)     2,000,000            
Profits interest, threshold price (in dollars per share) | $ / shares 14                
Profit Interest 3                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Profit interests (in shares)     3,000,000            
Profits interest, threshold price (in dollars per share) | $ / shares $ 16                
Lawrence Kingsley (Chairman of Board)                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Shares issued (in shares)     4,200,000            
Thomas Logan (CEO)                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Shares issued (in shares)     3,200,000            
Brian Schopfer (CFO)                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Shares issued (in shares)     700,000            
Minimum                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Number of trading days for determining the value per share 20 days                
Maximum                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Number of trading days for determining the value per share 30 days                
Class A Common Stock                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Stock-based compensation expense | $         $ 0.3 $ 0.3      
Common stock, shares outstanding (in shares) 18,750,000       218,177,832 200,298,834      
Class A Common Stock | 2021 Omnibus Incentive Plan                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Common stock, capital shares reserved for future issuance (in shares)   19,952,329   19,952,329       31,946,993  
Common stock outstanding, ownership percentage   3.00%   3.00%          
Common stock, shares outstanding (in shares)   9,976,164   9,976,164          
2021 Omnibus Incentive Plan                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Number of shares available for grant (in shares)         28,805,002        
RSUs                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Target percentage         100.00% 200.00%      
Expected period for recognition         1 year 2 months 12 days        
Restricted Stock                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Stock-based compensation expense | $             $ 0.0    
Shares issued (in shares)       0     0    
Shares reissued (in shares)       0     144,219    
Restricted Stock | Minimum                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Requisite service period         3 years        
Restricted Stock | Maximum                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Requisite service period         5 years        
Restricted Stock | Ordinary A shares of Mirion TopCo common stock                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Share-based compensation arrangement by share-based payment award, award vesting period   4 years              
Shares issued (in shares)   1,483,795              
PSUs                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Share-based compensation arrangement by share-based payment award, award vesting period         3 years        
Profit interests, percent     50.00%            
Expected period for recognition         1 year 2 months 12 days        
PSUs | Minimum                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Variable range, percentage   0.00%   0.00%          
PSUs | Maximum                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Variable range, percentage   200.00%   200.00%          
Founder Shares                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Share-based compensation arrangement by share-based payment award, award vesting period 5 years                
Founder Shares | Profit Interest 1                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Profits interest, threshold price (in dollars per share) | $ / shares $ 12                
Founder Shares | Profit Interest 2                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Profits interest, threshold price (in dollars per share) | $ / shares 14                
Founder Shares | Profit Interest 3                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Profits interest, threshold price (in dollars per share) | $ / shares $ 16                
Founder Shares | Minimum                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Number of trading days for determining the value per share 20 days                
Founder Shares | Maximum                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Number of trading days for determining the value per share 30 days