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Stock Option Plans - Additional information (Detail) - USD ($) $ / shares in Units, $ in Millions |  |  |  |  | 3 Months Ended | 9 Months Ended
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May 10, 2022 | Mar. 15, 2022 | Feb. 01, 2022 | Mar. 16, 2021 | Sep. 30, 2022 | Jun. 30, 2022 | Mar. 31, 2022 | Sep. 30, 2021 | Jun. 30, 2021 | Mar. 31, 2021 | Sep. 30, 2022 | Sep. 30, 2021
Stock Option Plans [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Compensation expense related to stock option grants |  |  |  |  | $ 7.5 | $ 7.2 | $ 5.7 | $ 4.7 | $ 4.5 | $ 3.7 | $ 20.4 | $ 12.9
Total intrinsic value of options exercised |  |  |  |  |  |  |  |  |  |  | 135.3 | $ 93.6
Total unrecognized compensation cost related to nonvested options |  |  |  |  | $ 102.9 |  |  |  |  |  | $ 102.9 |
Weighted average period, years |  |  |  |  |  |  |  |  |  |  | 4 years |
Black-Scholes Option Pricing Model [Member] |  |  |  |  |  |  |  |  |  |  |  |
Stock Option Plans [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Weighted average fair value per option for all options |  |  |  |  |  |  |  |  |  |  | $ 33.25 | $ 23.38
Long Term Incentive Plan [Member] |  |  |  |  |  |  |  |  |  |  |  |
Stock Option Plans [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Stock option granted, Share pool | 13,500,000 |  |  |  |  |  |  |  |  |  |  |
Shares against the pool | 3.8 |  |  |  |  |  |  |  |  |  |  |
Maximum number of shares available | 3,500,000 |  |  |  |  |  |  |  |  |  | 3,300,000 |
Number Of Periods Options Expire |  |  |  |  |  |  |  |  |  |  | 7 years |
Shares available for grant |  |  |  |  | 13,400,000 |  |  |  |  |  | 13,400,000 |
Long Term Incentive Plan [Member] | Officer and Key Employees [Member] |  |  |  |  |  |  |  |  |  |  |  |
Stock Option Plans [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Shares available for grant |  | 1,141,000 | 1,197,000 |  |  |  |  |  |  |  |  |
Long Term Incentive Plan [Member] | Maximum [Member] |  |  |  |  |  |  |  |  |  |  |  |
Stock Option Plans [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Minimum exercise price of stock options, percent of fair market value of a share of common stock on the date of grant |  |  |  |  |  |  |  |  |  |  | 100.00% |
2017 Long Term Incentive Plan [Member] | Officer and Key Employees [Member] |  |  |  |  |  |  |  |  |  |  |  |
Stock Option Plans [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Shares available for grant |  |  |  | 1,640,000 |  |  |  |  |  |  |  |
Stock options granted, exercise percentage, on the third anniversary date of the grant |  | 34.00% | 34.00% | 34.00% |  |  |  |  |  |  |  |
Stock options granted, exercise percentage, on the fourth anniversary date of the grant |  | 33.00% | 33.00% | 33.00% |  |  |  |  |  |  |  |
Stock options granted, exercise percentage, on the fifth anniversary date of the grant |  | 33.00% | 33.00% | 33.00% |  |  |  |  |  |  |  |
2017 Long Term Incentive Plan [Member] | Maximum [Member] |  |  |  |  |  |  |  |  |  |  |  |
Stock Option Plans [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Maximum period for the exercise of stock options, years |  |  |  |  |  |  |  |  |  |  | 7 years | 7 years
2017 Long Term Incentive Plan [Member] | Minimum [Member] |  |  |  |  |  |  |  |  |  |  |  |
Stock Option Plans [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Period of service from grant date stock options awarded not subject to forfeiture |  |  |  |  |  |  |  |  |  |  | 2 years | 2 years
2017 Long Term Incentive Plan [Member] | Minimum [Member] | Executive Officer [Member] |  |  |  |  |  |  |  |  |  |  |  |
Stock Option Plans [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Minimum age of employee with not subject to award forfeiture on condition compliance |  |  |  |  |  |  |  |  |  |  | 55 years | 55 years

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