Marketable Securities (Summary of available-for-sale securities ) (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Mar. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Marketable Securities, Realized Gain (Loss)	$ 3,000	$ 852,000	$ 236,000	$ 1,181,000
Aggregate Fair Value, Securities in a continuous loss position for less than 12 months	4,408,000		4,408,000
Aggregate Fair Value, Securities in a continuous loss position for more than 12 months	4,201,000		4,201,000
Aggregate Fair Value	8,609,000		8,609,000
Unrealized Losses, Securities in a continuous loss position for less than 12 months			147,000
Unrealized Losses, Securities in a continuous loss position for more than 12 months			39,000
Unrealized Losses			186,000
Foreign exchange contracts
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	18,144,000		18,144,000		$ 19,402,000
Gross Unrealized Gains	165,000				525,000
Gross Unrealized Losses	186,000				60,000
Estimated Fair Value	$ 18,123,000		$ 18,123,000		$ 19,867,000