Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 69,217	$ 44,862	$ 171,211	$ 185,056
Other comprehensive income (loss):
Foreign currency translation gain (loss)	1,945	(1,015)	(1,436)	(8,468)
Unrealized loss on derivative instrument	(1,392)		(1,392)
Net unrealized gains on marketable securities	8	234	522	356
Other comprehensive income (loss)	561	(781)	(2,306)	(8,112)
Comprehensive income	$ 69,778	$ 44,081	$ 168,905	$ 176,944