Common Stock and Stock Plans (Tables)

12 Months Ended

Mar. 31, 2020

Equity [Abstract]

Summary of Stock-based Compensation Expense

Total stock-based compensation expense recognized in accordance with the authoritative guidance for share-based payments was as follows:

	Fiscal Years Ended
	March 31, 2020			March 31, 2019			March 31, 2018
	(In thousands)
Stock-based compensation expense before taxes	$	86,553		$	79,599		$	68,545
Related income tax benefits		(20,388	)		(18,824	)		(16,278	)
Stock-based compensation expense, net of taxes	$	66,165		$	60,775		$	52,267

Summary of Employee Stock Options and Employee Stock Purchase Plan Weighted Average Assumptions

The weighted average assumptions (annualized percentages) used in the Black-Scholes model and Monte Carlo simulation were as follows:

	Employee Stock Options									TSR Performance Stock Options									Employee Stock Purchase Plan
	Fiscal Year 2020			Fiscal Year 2019			Fiscal Year 2018			Fiscal Year 2020			Fiscal Year 2019			Fiscal Year 2018			Fiscal Year 2020			Fiscal Year 2019			Fiscal Year 2018
Volatility		27.9	%		27.9	%		30.4	%		27.7	%		28.2	%		27.5	%		24.6	%		32.8	%		22.0	%
Risk-free interest rate		1.3	%		2.8	%		1.9	%		1.7	%		2.8	%		1.9	%		1.8	%		2.4	%		1.3	%
Dividend yield		0.0	%		0.0	%		0.0	%		0.0	%		0.0	%		0.0	%		0.0	%		0.0	%		0.0	%
Expected life	5.0 years			5.0 years			5.4 years			5.0 years			5.0 years			5.0 years			0.5 years			0.5 years			0.5 years

Summary of Employee Stock Option Activity and TSR Performance Stock Option Activity

A summary of stock option activity for fiscal year 2020 is presented below:

	Number of Shares			Weighted Average Exercise Price per Share		Weighted Average Remaining Contractual Term in Years		Aggregate Intrinsic Value (In thousands)
Outstanding at March 31, 2019		1,531,500		$	64.87
Options granted		39,000			74.64
Options canceled		(5,000	)		77.47
Options exercised		(340,267	)		61.89
Outstanding at March 31, 2020		1,225,233		$	65.96		1.91	$	—
Vested and exercisable at March 31, 2020		1,076,983		$	65.30		1.71	$	—

A summary of TSR performance stock option activity for fiscal year 2020 is presented below:

	Number of Shares (1)		Weighted Average Exercise Price per Share		Weighted Average Remaining Contractual Term in Years		Aggregate Intrinsic Value (In thousands)
Outstanding at March 31, 2019		1,027,500	$	71.34
TSR performance options granted		603,306		71.83
TSR performance options canceled		—		—
TSR performance options exercised		—		—
Outstanding at March 31, 2020		1,630,806	$	71.52		4.70	$	—
Vested and exercisable at March 31, 2020		—	$	—		—	$	—

(1) Number of shares is based on the target number of options under each TSR performance stock option.

Summary of Restricted Stock Unit Activity

A summary of restricted stock unit activity for fiscal year 2020 is presented below:

	Number of Restricted Stock Units			Weighted Average Grant Date Fair Value per Share
Outstanding at March 31, 2019		2,904,242		$	67.99
Awarded		1,284,684			71.59
Forfeited		(93,092	)		70.26
Vested		(1,075,526	)		68.27
Outstanding at March 31, 2020		3,020,308		$	69.35
Vested and deferred at March 31, 2020		182,334		$	44.53