Components of Income Tax Provision (Detail) - USD ($) $ in Thousands	3 Months Ended																12 Months Ended
	Mar. 31, 2021	[1]	Dec. 31, 2020	[1]	Sep. 30, 2020	[1]	Jun. 30, 2020	[1]	Mar. 31, 2020	[1]	Dec. 31, 2019	[1]	Sep. 30, 2019	[1]	Jun. 30, 2019	[1]	Mar. 31, 2021		Mar. 31, 2020		Mar. 31, 2019
Income Tax Disclosure [Abstract]
Income (loss) before income taxes																	$ 249,204		$ 214,825		$ 223,340
Income (loss) before income taxes, foreign																	39,016		42,000		40,020
Income (loss) before income taxes																	288,220		256,825		263,360
Current income tax provision, Federal																	8,624
Current income tax provision, State																	12,379		6,563		564
Current income tax provision, Foreign																	12,312		14,300		11,525
Current income tax provision																	33,315		20,863		12,089
Deferred income tax provision, Federal																	30,413		33,239		(7,153)
Deferred income tax provision, State																	(2,382)		1,584		(1,503)
Deferred income tax provision, Foreign																	1,349		(1,870)		911
Deferred income tax provision																	29,380		32,953		(7,745)
Total income tax provision	$ 16,638		$ 18,867		$ 10,702		$ 16,488		$ 7,515		$ 27,799		$ 4,287		$ 14,215		$ 62,695	[1]	$ 53,816	[1]	$ 4,344

[1] The income tax provision for the years ended March 31, 2021 and 2020 included excess tax benefits of $12.1 million and $14.8 million, respectively. These recognized excess tax benefits resulted from restricted stock units that vested or stock options that were exercised during the years ended March 31, 2021 and 2020.