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Business Combinations - Summary of Unaudited Pro Forma Historical Results (Detail) - USD ($) $ / shares in Units, $ in Millions | 3 Months Ended | 9 Months Ended
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Sep. 30, 2021 | Sep. 30, 2020 | Sep. 30, 2021 | Sep. 30, 2020
Business Combinations [Abstract] |  |  |  |
Total revenues | $ 2,140.7 | $ 1,899.6 | $ 6,278.4 | $ 5,435.7
Net earnings attributable to controlling interests | $ 225.0 | $ 181.6 | $ 801.9 | $ 685.9
Basic net earnings per share | $ 1.09 | $ 0.94 | $ 3.99 | $ 3.60
Diluted net earnings per share | $ 1.06 | $ 0.92 | $ 3.90 | $ 3.52

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