Basis of Preparation and Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Apr. 01, 2017
Summary Of Significant Accounting Policy [Line Items]
Cumulative effect to increase retained earnings and deferred tax assets				$ 77,081
Excess tax benefits related to restricted stock unit vestings or stock option exercises, decrease in financing activities			$ 4,595
Excess tax benefits related to restricted stock unit vestings or stock option exercises, increase in operating activities			$ 4,595
ASU 2016-09
Summary Of Significant Accounting Policy [Line Items]
Excess tax benefit	$ 3,200	$ 24,500
Excess tax benefits related to restricted stock unit vestings or stock option exercises, decrease in financing activities		24,500
Excess tax benefits related to restricted stock unit vestings or stock option exercises, increase in operating activities		$ 24,500
Increase additional paid in capital				1,800
Increase deferred tax assets				700
Decrease retained earnings				(1,100)
Adjustment to Increase Retained Earnings and Deferred Tax Assets | ASU 2016-09
Summary Of Significant Accounting Policy [Line Items]
Cumulative effect to increase retained earnings and deferred tax assets				$ 76,400