Common Stock and Stock Plans - Summary of Stock-based Compensation Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-based compensation expense before taxes	$ 84,879	$ 86,553	$ 79,599
Related income tax benefits	(19,485)	(20,388)	(18,824)
Stock-based compensation expense, net of taxes	$ 65,394	$ 66,165	$ 60,775

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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