Business Combinations, Acquisitions, and Business Disposals - Schedule of Business Acquisition, Pro Forma Information (Details) - Certrec - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
Business Combination [Line Items]
Total revenues	$ 1,043.2	$ 974.0
Net income (loss)	29.0	(61.2)
Net income (loss) attributable to Mirion Technologies, Inc. stockholders	$ 28.0	$ (60.7)