Segment Information - Revenue by Geographic Area (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information [Line Items]
Total revenues	$ 554,278	$ 592,256	$ 1,084,766	$ 1,129,293
U.S. Customers [Member]
Segment Reporting Information [Line Items]
Total revenues	513,015	536,284	1,011,530	997,567
Non U.S. Customers [Member]
Segment Reporting Information [Line Items]
Total revenues	$ 41,263	$ 55,972	$ 73,236	$ 131,726