Net Income Per Share and Stockholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions		3 Months Ended			6 Months Ended
	Jun. 14, 2019	Sep. 30, 2020	Sep. 30, 2019	Jun. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Equity Class Of Treasury Stock [Line Items]
Cash dividend declared				$ 0.09
Dividend payment				$ 81,600
Additional stock-based compensation expense		$ 5,496	$ 3,171		$ 11,095	$ 5,012
Cost of Goods Sold - ESOP special dividend compensation and Selling, General and Administrative Expenses [Member]
Equity Class Of Treasury Stock [Line Items]
Additional stock-based compensation expense				$ 246,800
ESOP [Member]
Equity Class Of Treasury Stock [Line Items]
Number of redeemable convertible preferred stock allocated to ESOP participants				11.6
Amount of dividend from unallocated redeemable convertible preferred stock held in the ESOP trust to repay ESOP loan				$ 12,000
Special Dividend [Member]
Equity Class Of Treasury Stock [Line Items]
Cash dividend declared				$ 1.00
Dividend payable date				Jun. 14, 2019
Dividend payable, date of record				Jun. 03, 2019
Special Dividend [Member] | ESOP [Member]
Equity Class Of Treasury Stock [Line Items]
Additional stock-based compensation expense	$ 246,800