Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 203,009	$ 259,016	$ 112,170
Other comprehensive (loss) income:
Foreign currency translation (loss) gain	(1,832)	(11,431)	16,862
Unrealized gain on derivative instrument	3,999
Net unrealized gain (loss) on marketable securities	1,333	946	(460)
Other comprehensive income (loss)	3,500	(10,485)	16,402
Comprehensive income	$ 206,509	$ 248,531	$ 128,572