Employee Stock Purchase Plan - Summary of Employee Stock Purchase Plan (Detail) (USD $)	12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2012
Employee Stock Purchase Plan [Line Items]
Employee contributions	$ 346,000	$ 313,000	$ 321,000
Employee Stock [Member]
Employee Stock Purchase Plan [Line Items]
Shares acquired	8,489	14,056	16,430
Average purchase price	$ 40.71	$ 22.30	$ 19.54