STOCK-BASED COMPENSATION (Tables)

6 Months Ended

Sep. 30, 2012

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Stock-Based Compensation Expense Included in Statements of Operations [Table Text Block]

The following table summarizes the amount of stock-based compensation included in the Condensed consolidated statements of operations:

	Three Months Ended						Six Months Ended
	September 30,						September 30,
(in thousands)	2012			2011			2012			2011
Cost of revenues	$	526		$	559		$	1,122		$	1,105
Research, development and engineering	1,256			1,028			2,380			1,975
Selling, general and administrative	3,080			2,921			5,980			5,608
Stock-based compensation included in operating expenses	4,336			3,949			8,360			7,583
Total stock-based compensation	4,862			4,508			9,482			8,688
Income tax benefit	(1,532		)	(1,441		)	(2,914		)	(2,723		)
Total stock-based compensation, net of tax	$	3,330		$	3,067		$	6,568		$	5,965

Summary of Stock Option Activity [Table Text Block]

The following is a summary of the Company’s stock option activity during the six months ended September 30, 2012:

	Options Outstanding
	Number of Shares		Weighted Average Exercise Price		Weighted Average Remaining Contractual Life	Aggregate Intrinsic Value
	(in thousands)				(in years)	(in thousands)
Outstanding at March 31, 2012	3,304		$	26.47
Options granted	266		$	33.40
Options exercised	(390	)	$	24.11
Options forfeited or expired	(140	)	$	34.91
Outstanding at September 30, 2012	3,040		$	27.00	3.7	$	26,109
Vested and expected to vest at September 30, 2012	3,005		$	26.91	3.6	$	26,038
Exercisable at September 30, 2012	2,200		$	24.45	2.8	$	24,183

Summary of Restricted Stock Activity [Table Text Block]

Restricted stock consists of awards of restricted stock and restricted stock units ("RSUs"). The following is a summary of the Company’s restricted stock activity during the six months ended September 30, 2012:

	Number of Shares		Weighted Average Grant Date Fair Value
	(in thousands)
Non-vested at March 31, 2012	815		$	33.37
Restricted stock granted	552		$	32.05
Restricted stock vested	(150	)	$	32.80
Restricted stock forfeited	(51	)	$	31.73
Non-vested at September 30, 2012	1,166		$	32.89

Valuation Assumptions [Table Text Block]

The fair value of stock options granted, and purchase rights under the ESPP, during the respective periods, are estimated on the date of grant using the following weighted average assumptions:

	Three Months Ended						Six Months Ended
	September 30,						September 30,
Employee Stock Options	2012			2011			2012			2011
Expected volatility	43.5		%	44.7		%	42.2		%	44.4		%
Risk-free interest rate	0.5		%	0.6		%	0.6		%	1.2		%
Expected dividends	1.3		%	0.6		%	1.3		%	0.6		%
Expected life (in years)	4.3			4.0			4.3			4.0
Weighted-average grant date fair value	$	10.84		$	10.85		$	10.43		$	12.18
ESPP
Expected volatility	38.4		%	38.7		%	38.4		%	38.7		%
Risk-free interest rate	0.1		%	0.1		%	0.1		%	0.1		%
Expected dividends	1.1		%	0.6		%	1.1		%	0.6		%
Expected life (in years)	0.5			0.5			0.5			0.5
Weighted-average grant date fair value	$	8.95		$	8.00		$	8.95		$	8.00