FINANCIAL INSTRUMENTS: (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Mar. 31, 2015
Fair value of assets and liabilities
Other current assets	$ 37,807	$ 34,975
Fair value measurements on recurring basis | Total
Fair value of assets and liabilities
Other current assets	12,752
Total assets	12,752
Other accrued expenses	269
Total liabilities	269
Fair value measurements on recurring basis | Level 1
Fair value of assets and liabilities
Other current assets	12,752
Total assets	12,752
Fair value measurements on recurring basis | Level 2
Fair value of assets and liabilities
Other accrued expenses	269
Total liabilities	$ 269