Marketable Securities (Summary of available-for-sale securities ) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	$ 2,971	$ 3,040
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	2,963	0
Aggregate fair value	5,934	3,040
Equity securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	20,078	21,635
Gross Unrealized Gains	2,013	2,335
Gross Unrealized Losses	150	19
Estimated Fair Value	21,941	23,951
Securities in a continuous loss position for less than 12 months	55	19
Securities in a continuous loss position for more than 12 months	95	0
Unrealized losses	$ 150	$ 19