Financial Instruments (Details) (USD $)	12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2012
Statement
Trading investments for deferred compensation plan:	$ 16,611,000	$ 15,599,000
Entity's normal operating cycle period	1 year
Unrealized trading gains (losses) included in other income (expense), net	400,000	500,000	100,000
Level 1
Statement
Cash equivalents	200,641,000	119,073,000
Cash equivalents	200,641,000	119,073,000
Trading investments for deferred compensation plan:	16,611,000	15,599,000
Level 1 | Money market funds
Statement
Trading investments for deferred compensation plan:	3,139,000	4,220,000
Level 1 | Mutual funds
Statement
Trading investments for deferred compensation plan:	13,472,000	11,379,000
Level 2
Statement
Foreign exchange derivative assets	155,000	1,197,000
Foreign exchange derivative liabilities	$ 701,000	$ 707,000