FAIR VALUE OF FINANCIAL INSTRUMENTS: - (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Mar. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other current assets	$ 41,145	$ 48,310
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other current assets	13,551	12,716
Total assets	13,551	12,716
Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other current assets	13,551	12,716
Total assets	13,551	12,716
Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other current assets	0	0
Total assets	0	0
Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other current assets	0	0
Total assets	$ 0	$ 0