OTHER ACCRUED EXPENSES: (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Mar. 31, 2017
Other Accrued Expenses [Abstract].
Accrued purchase consideration	$ 5,880	$ 5,880
Liabilities of non-qualified retirement plan	13,519	12,716
Other accrued expenses	38,515	41,265
Other accrued expenses	$ 57,914	$ 59,861