Stock Options and Stock-Based Compensation - Stock Options (Detail) - $ / shares	12 Months Ended
Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding, beginning balance, Shares	723,876	937,158	1,029,103
Options granted, Shares	168,300	130,200	234,175
Options exercised, Shares	(209,301)	(298,570)	(278,094)
Options cancelled/forfeited, Shares	(31,018)	(44,912)	(48,026)
Options outstanding, ending balance, Shares	651,857	723,876	937,158
Options granted, weighted average exercise price	$ 159.43	$ 161.95	$ 81.12
Options exercised, weighted average exercise price	63.21	55.44	44.17
Options cancelled/forfeited, weighted average exercise price	140.38	79.30	61.26
Weighted average exercise price per share	$ 108.10	$ 84.55	$ 64.28
Options available for future grants	657,972	805,097	880,542
Exercisable options	319,703	354,460	421,964
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Price range of outstanding options	$ 33.16	$ 22.07	$ 21.87
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Price range of outstanding options	$ 197.16	$ 197.16	$ 103.31

Share based compensation shares authorized under stock option plans options available for future grants.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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For presentations that combine terminations, the number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan or that expired.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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Weighted average price of options that were either forfeited or expired.

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Gross number of share options (or share units) granted during the period.

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Number of options outstanding, including both vested and non-vested options.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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The number of shares reserved for issuance pertaining to the outstanding exercisable stock options as of the balance sheet date in the customized range of exercise prices for which the market and performance vesting condition has been satisfied.

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The weighted average price as of the balance sheet date at which grantees could acquire the underlying shares with respect to all outstanding stock options which are in the customized range of exercise prices.

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Number of share options (or share units) exercised during the current period.

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