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Share-Based Compensation - Additional Information (Detail) - Restricted Stock [Member] - USD ($) | 12 Months Ended
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Jun. 30, 2021 | Jun. 30, 2020 | Jun. 30, 2019
Disclosure Of Compensation Related Costs Share Based Payments [Line Items] |  |  |
Number of shares issued | 0 |  |
Shares Vested period | 4 years |  |
Share based comepnsation arrangement,award vesting conditions | The Company’s board of directors issued ordinary A shares of Mirion TopCo common stock for the fair value at the time of issuance. In total, the Company has issued 1,483,795 shares as of June 30, 2021. The shares were issued subject to certain vesting conditions, restrictions on transfer and repurchase rights (further collectively referred to as “Shares”) by Mirion TopCo, other employees of the Company or by investors in Mirion TopCo. Under the service vesting conditions, the Shares, vest over four years, with one-quarter vesting after one year of service, and the remainder vesting in equal installments over the subsequent thirty-six months. |  |
Share based compensation arrangement,Requisite Service Period | 4 years |  |
Number of shares existed or granted during period | 0 | 200,000 | 0
Number of shares reissued to members of management team |  | 144,219 |
Share based compensation expense | $ 0.0 | $ 200,000 | $ 100,000
Unrecognised compensation expense | $ 0 |  |
Ordinary A shares of Mirion TopCo common stock [Member] |  |  |
Disclosure Of Compensation Related Costs Share Based Payments [Line Items] |  |  |
Number of shares issued | 1,483,795 |  |

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- Definition Share based compensation arrangement by share based payment award,number of shares reissued. + References No definition available. + Details
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- Definition Estimated period over which an employee is required to provide service in exchange for the equity-based payment award, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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