Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 62,213	$ 13,071	$ 106,801	$ 101,994
Other comprehensive income (loss):
Foreign currency translation gains (losses)	2,416	(5,716)	3,776	(3,382)
Unrealized losses on derivative instrument	(266)		(726)
Net unrealized (losses) gains on marketable securities	(814)	(85)	940	515
Other comprehensive income	1,336	(5,801)	3,990	(2,867)
Comprehensive income	$ 63,549	$ 7,270	$ 110,791	$ 99,127