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Business Combinations and Acquisitions - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions |  |  |  | 1 Months Ended | 2 Months Ended | 3 Months Ended | 4 Months Ended | 12 Months Ended |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Nov. 01, 2023 | Aug. 01, 2022 | Oct. 20, 2021 | Feb. 28, 2021 | Dec. 31, 2021 | Mar. 31, 2023 | Oct. 19, 2021 | Dec. 31, 2023 | Dec. 31, 2022 | Jun. 30, 2021 | Jun. 30, 2020 | Dec. 01, 2021 | Dec. 18, 2020
Business Combination, Separately Recognized Transactions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Goodwill |  |  |  |  | $ 1,662.6 |  |  | $ 1,447.6 | $ 1,418.0 |  |  |  |
Business Combination and other acquisitions - measurement period adjustments |  |  |  |  |  |  |  |  | $ 3.4 |  |  |  |
Measurement Period Adjustment |  |  |  |  |  |  |  | $ 0.9 |  |  |  |  |
Income tax at U.S. Federal statutory rate |  |  |  |  | 21.00% |  |  | 21.00% | 21.00% |  |  |  |
EC5 |  |  |  |  |  |  |  |  |  |  |  |  |
Business Combination, Separately Recognized Transactions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Cash consideration paid | $ 31.4 |  |  |  |  |  |  |  |  |  |  |  |
Total amortizable intangible assets | 14.5 |  |  |  |  |  |  |  |  |  |  |  |
Goodwill | 17.4 |  |  |  |  |  |  |  |  |  |  |  |
Liabilities | $ (0.5) |  |  |  |  |  |  |  |  |  |  |  |
Critical Infrastructure |  |  |  |  |  |  |  |  |  |  |  |  |
Business Combination, Separately Recognized Transactions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Cash consideration paid |  | $ 6.6 |  |  |  |  |  |  |  |  |  |  |
Business Combination and other acquisitions - measurement period adjustments |  |  |  |  |  | $ 0.9 |  |  |  |  |  |  |
Measurement Period Adjustment |  |  |  |  |  |  |  | $ 3.9 |  |  |  |  |
Increase (decrease) in noncurrent deferred tax assets and liabilities, net |  |  |  |  |  |  |  | (4.3) |  |  |  |  |
Decrease in noncontrolling interest |  |  |  |  |  |  |  | 1.8 |  |  |  |  |
Increase (decrease) in other noncurrent assets and liabilities, net |  |  |  |  |  |  |  | (1.4) |  |  |  |  |
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Liabilities, Other Accrued |  |  |  |  |  | $ (0.9) |  |  |  |  |  |  |
CIRS |  |  |  |  |  |  |  |  |  |  |  |  |
Business Combination, Separately Recognized Transactions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Equity interest, acquired percentage |  |  |  |  |  |  |  |  |  |  |  | 100.00% |
Measurement Period Adjustment |  |  |  |  |  |  |  | (1.0) |  |  |  |  |
Increase (decrease) in noncurrent deferred tax assets and liabilities, net |  |  |  |  |  |  |  | $ (1.0) |  |  |  |  |
CIRS | Medical |  |  |  |  |  |  |  |  |  |  |  |  |
Business Combination, Separately Recognized Transactions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Total amortizable intangible assets |  |  |  |  |  |  |  |  |  |  |  | $ 21.8 |
Goodwill |  |  |  |  |  |  |  |  |  |  |  | $ 34.0 |
Transaction expenses |  |  |  |  |  |  |  |  | $ 0.4 |  |  |  |
Intermediate Co |  |  |  |  |  |  |  |  |  |  |  |  |
Business Combination, Separately Recognized Transactions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Cash consideration paid |  |  | $ 1,300.0 |  |  |  |  |  |  |  |  |  |
Business acquisition share price (in dollars per share) |  |  | $ 10.00 |  |  |  |  |  |  |  |  |  |
Intermediate Co | Class A Common Stock |  |  |  |  |  |  |  |  |  |  |  |  |
Business Combination, Separately Recognized Transactions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Business acquisition equity interest issued or issuable (in shares) |  |  | 30,401,902 |  |  |  |  |  |  |  |  |  |
Intermediate Co | Class B Common Stock |  |  |  |  |  |  |  |  |  |  |  |  |
Business Combination, Separately Recognized Transactions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Business acquisition equity interest issued or issuable (in shares) |  |  | 8,560,540 |  |  |  |  | 7,787,333 |  |  |  |  |
Mirion |  |  |  |  |  |  |  |  |  |  |  |  |
Business Combination, Separately Recognized Transactions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Total amortizable intangible assets |  |  | $ 821.0 |  |  |  |  |  |  |  |  |  |
Goodwill |  |  | 1,642.9 |  |  |  |  |  |  |  |  |  |
Pro forma adjustments |  |  |  |  | $ 2.2 |  | $ 26.2 |  |  |  |  |  |
Income tax at U.S. Federal statutory rate |  |  |  |  | 25.00% |  | 25.00% |  |  | 25.00% |  |  |
Mirion | Medical |  |  |  |  |  |  |  |  |  |  |  |  |
Business Combination, Separately Recognized Transactions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Total amortizable intangible assets |  |  | 330.5 |  |  |  |  |  |  |  |  |  |
Goodwill |  |  | $ 680.4 |  |  |  |  |  |  |  |  |  |
Mirion | Fair Value Adjustment to Inventory |  |  |  |  |  |  |  |  |  |  |  |  |
Business Combination, Separately Recognized Transactions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Pro forma adjustments |  |  |  |  | $ 15.8 |  | $ 15.8 |  |  | $ 15.8 |  |  |
Mirion | Acquisition-related Costs |  |  |  |  |  |  |  |  |  |  |  |  |
Business Combination, Separately Recognized Transactions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Pro forma adjustments |  |  |  |  | $ 28.4 |  | $ 28.4 |  |  | 28.4 |  |  |
Sun Nuclear |  |  |  |  |  |  |  |  |  |  |  |  |
Business Combination, Separately Recognized Transactions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Equity interest, acquired percentage |  |  |  |  |  |  |  |  |  |  |  |  | 100.00%
Sun Nuclear | Medical |  |  |  |  |  |  |  |  |  |  |  |  |
Business Combination, Separately Recognized Transactions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Cash consideration paid |  |  |  | $ 261.9 |  |  |  |  |  |  |  |  |
Total amortizable intangible assets |  |  |  |  |  |  |  |  |  |  |  |  | $ 125.5
Goodwill |  |  |  |  |  |  |  |  |  |  |  |  | $ 130.2
Transaction expenses |  |  |  |  |  |  |  |  |  | $ 1.2 |  |  |
Biodex and SNC |  |  |  |  |  |  |  |  |  |  |  |  |
Business Combination, Separately Recognized Transactions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Income tax at U.S. Federal statutory rate |  |  |  |  |  |  |  |  |  | 25.00% | 25.00% |  |
Biodex and SNC | Fair Value Adjustment to Inventory |  |  |  |  |  |  |  |  |  |  |  |  |
Business Combination, Separately Recognized Transactions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Pro forma adjustments |  |  |  |  |  |  |  |  |  | $ 5.2 | $ 5.2 |  |
Biodex and SNC | Acquisition-related Costs |  |  |  |  |  |  |  |  |  |  |  |  |
Business Combination, Separately Recognized Transactions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Pro forma adjustments |  |  |  |  |  |  |  |  |  | 4.8 | 4.8 |  |
Biodex and SNC | Reduction In Revenues Due To The Elimination Of Deferred Contract Revenue |  |  |  |  |  |  |  |  |  |  |  |  |
Business Combination, Separately Recognized Transactions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Pro forma adjustments |  |  |  |  |  |  |  |  |  | $ 14.8 | $ 14.8 |  |

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