COMPUTATION OF EARNINGS PER COMMON SHARE (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended	9 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2014	Dec. 31, 2013
Earnings Per Share [Abstract]
Net income	$ 30,384us-gaap_NetIncomeLoss	$ 34,383us-gaap_NetIncomeLoss	$ 86,477us-gaap_NetIncomeLoss	$ 84,474us-gaap_NetIncomeLoss
Earnings Per Share, Basic and Diluted [Abstract]
Weighted average common shares-basic	41,901	42,441	41,780	42,647
Dilutive effect of employee equity incentive plans	799	787	894	907
Weighted average common shares-diluted	42,700	43,228	42,674	43,554
Basic earnings per common share	$ 0.73us-gaap_EarningsPerShareBasic	$ 0.81us-gaap_EarningsPerShareBasic	$ 2.07us-gaap_EarningsPerShareBasic	$ 1.98us-gaap_EarningsPerShareBasic
Diluted earnings per common share	$ 0.71us-gaap_EarningsPerShareDiluted	$ 0.80us-gaap_EarningsPerShareDiluted	$ 2.03us-gaap_EarningsPerShareDiluted	$ 1.94us-gaap_EarningsPerShareDiluted
Potentially dilutive securities excluded from diluted earnings per common share because their effect is anti-dilutive	130	268	442	173

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.

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