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Description of Organization and Business Operations - Additional Information (Detail) - USD ($) |  |  | 6 Months Ended | 12 Months Ended |  |
--- | --- | --- | --- | --- | --- | ---
Jul. 02, 2020 | Jun. 30, 2020 | Jun. 30, 2021 | Jun. 30, 2020 | Dec. 31, 2020 | Sep. 30, 2020 | Dec. 31, 2019
GS Acquisition Holdings Corp II [Member] |  |  |  |  |  |  |
Organization And Business Operations [Line Items] |  |  |  |  |  |  |
Deposit to trust account |  | $ 750,000,000 |  | $ 750,000,000 |  |  |
Percentage of public shares required to repurchase if business combination is not completed within specified period |  |  | 100.00% |  | 100.00% |  |
Balance in trust account |  |  | $ 750,089,714 |  | $ 750,067,041 |  |
Accrued dividends |  |  | $ 3,758 |  | $ 3,883 |  | $ 0
Percentage of fair market value to that of balance in the trust account |  |  | 80.00% |  | 80.00% |  |
Interest to pay dissolution expenses |  |  | $ 100,000 |  | $ 100,000 |  |
Period from closing of public offering to complete business combination |  |  | 24 months |  | 24 months |  |
Cash |  |  | $ 799,624 |  | $ 383,246 |  | $ 5,000
Common Class A [Member] |  |  |  |  |  |  |
Organization And Business Operations [Line Items] |  |  |  |  |  |  |
Common stock, par value |  | $ 0.01 | $ 0.01 | $ 0.01 |  |  |
Common Class A [Member] | GS Acquisition Holdings Corp II [Member] |  |  |  |  |  |  |
Organization And Business Operations [Line Items] |  |  |  |  |  |  |
Shares issued during the period,shares |  |  | 75,000,000 |  | 75,000,000 |  |
Common stock, par value | $ 0.0001 |  | $ 0.0001 |  | $ 0.0001 | $ 0.0001 | $ 0.0001
Common Class B [Member] |  |  |  |  |  |  |
Organization And Business Operations [Line Items] |  |  |  |  |  |  |
Common stock, par value |  | $ 0.01 | 0.01 | $ 0.01 |  |  |
Common Class B [Member] | GS Acquisition Holdings Corp II [Member] |  |  |  |  |  |  |
Organization And Business Operations [Line Items] |  |  |  |  |  |  |
Common stock, par value |  |  | $ 0.0001 |  | $ 0.0001 |  | $ 0.0001
Mirion Technologies And The Charter Parties [Member] | GS Acquisition Holdings Corp II [Member] |  |  |  |  |  |  |
Organization And Business Operations [Line Items] |  |  |  |  |  |  |
Business combination consideration transferred |  |  | $ 1,700,000,000 |  |  |  |
Mirion Technologies And The Charter Parties [Member] | Pipe Investors [Member] | Common Class A [Member] | GS Acquisition Holdings Corp II [Member] |  |  |  |  |  |  |
Organization And Business Operations [Line Items] |  |  |  |  |  |  |
Business acquisition equity interest issued or issuable, number of shares |  |  | 90,000,000 |  |  |  |
Business acquisition, equity interest issued or issuable value assigned |  |  | $ 900,000,000 |  |  |  |
Mirion Technologies And The Charter Parties [Member] | Minimum Cash Condition [Member] | GS Acquisition Holdings Corp II [Member] |  |  |  |  |  |  |
Organization And Business Operations [Line Items] |  |  |  |  |  |  |
Cash |  |  | 50,000,000 |  |  |  |
Mirion Technologies And The Charter Parties [Member] | Minimum Cash Condition [Member] | Common Class A [Member] | GS Acquisition Holdings Corp II [Member] |  |  |  |  |  |  |
Organization And Business Operations [Line Items] |  |  |  |  |  |  |
Payments to acquire businesses gross |  |  | $ 1,310,000,000 |  |  |  |
Mirion Technologies And The Charter Parties [Member] | Minimum Cash Condition [Member] | Common Class B [Member] | GS Acquisition Holdings Corp II [Member] |  |  |  |  |  |  |
Organization And Business Operations [Line Items] |  |  |  |  |  |  |
Common stock, par value |  |  | $ 0.01 |  |  |  |
Asset Held in Trust [Member] | GS Acquisition Holdings Corp II [Member] |  |  |  |  |  |  |
Organization And Business Operations [Line Items] |  |  |  |  |  |  |
Accrued dividends |  |  | $ 3,758 |  | $ 3,883 |  |
IPO [Member] | GS Acquisition Holdings Corp II [Member] |  |  |  |  |  |  |
Organization And Business Operations [Line Items] |  |  |  |  |  |  |
Shares issued during the period,shares | 75,000,000 |  |  |  |  |  |
IPO [Member] | Common Class A [Member] | GS Acquisition Holdings Corp II [Member] |  |  |  |  |  |  |
Organization And Business Operations [Line Items] |  |  |  |  |  |  |
Common stock, par value |  |  | $ 0.0001 |  | $ 0.0001 |  |
Underwriter Option [Member] | IPO [Member] | GS Acquisition Holdings Corp II [Member] |  |  |  |  |  |  |
Organization And Business Operations [Line Items] |  |  |  |  |  |  |
Shares issued during the period,shares | 5,000,000 |  |  |  |  |  |
Maximum [Member] | GS Acquisition Holdings Corp II [Member] |  |  |  |  |  |  |
Organization And Business Operations [Line Items] |  |  |  |  |  |  |
Payment of deferred underwriting commissions |  |  | $ 5,000,001 |  | $ 5,000,001 |  |
Minimum [Member] | Mirion Technologies And The Charter Parties [Member] | Minimum Cash Condition [Member] | GS Acquisition Holdings Corp II [Member] |  |  |  |  |  |  |
Organization And Business Operations [Line Items] |  |  |  |  |  |  |
Payments to acquire businesses gross |  |  | $ 1,310,000,000 |  |  |  |
Minimum [Member] | Mirion Technologies And The Charter Parties [Member] | Minimum Cash Condition [Member] | Common Class A [Member] | GS Acquisition Holdings Corp II [Member] |  |  |  |  |  |  |
Organization And Business Operations [Line Items] |  |  |  |  |  |  |
Common stock, par value |  |  | $ 0.01 |  |  |  |

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