Calculation of Basic and Diluted Common Shares Outstanding (Detail)	3 Months Ended		6 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Earning Per Share [Abstract]
Weighted-Average Shares of Common Stock Outstanding	49,591,495	49,012,045	49,546,916	48,984,038
Assumed Exercise of Outstanding Dilutive Options	1,423,211	1,682,592	1,453,437	1,692,782
Less: Shares Repurchased from Assumed Proceeds of Assumed Exercised Options	(891,837)	(1,134,329)	(933,050)	(1,137,668)
Restricted Shares	304,417	299,792	290,611	296,230
Weighted-Average Common and Common Equivalent Shares Outstanding	50,427,286	49,860,100	50,357,914	49,835,382
Shares Excluded Due to Anti-dilution Effects	218,636	121,957	170,227	71,479