Calculation of Basic and Diluted Common Shares Outstanding (Detail) - shares	3 Months Ended	6 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Earnings Per Share [Abstract]
Weighted Average Shares of Common Stock Outstanding	41,572,127	47,219,532	42,714,896	47,453,655
Assumed Exercise of Outstanding Dilutive Options	649,394	785,848	700,024	807,861
Less Shares Repurchased from Proceeds of Assumed Exercised Options	(509,571)	(588,900)	(550,609)	(580,350)
Restricted Stock Units	121,825	147,338	121,404	172,306
Weighted Average Common Stock and Dilutive Securities Outstanding	41,833,775	47,563,818	42,985,715	47,853,472
Shares Excluded Due to Anti-dilution Effects	448,354	181,412	388,058	163,450

Shares repurchased from assumed proceeds of assumed exercised options.

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- Definition

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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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of contingently issuable shares. Contingently issuable shares are those shares that are issuable for little or no cash contingent on certain conditions being met.

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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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The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

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Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

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