Segment Information - Revenue Information by Geographic Area (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Segment Reporting Information [Line Items]
Total revenues	$ 2,309,238	$ 2,068,258	$ 1,594,625
U.S. Customers [Member]
Segment Reporting Information [Line Items]
Total revenues	2,057,458	1,836,304	1,403,473
Non U.S. Customers [Member]
Segment Reporting Information [Line Items]
Total revenues	$ 251,780	$ 231,954	$ 191,152