Components of Stock-Based Compensation (Detail) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	$ 4,799	$ 4,290
Restricted stock units
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	3,903	3,420
Stock Options
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	819	799
Employee Stock Purchase Plan
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	$ 77	$ 71