GOODWILL AND INTANGIBLE ASSETS: - Estimated future amortization expenses (Details) - USD ($) $ in Thousands	9 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Mar. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization expense	$ 13,000	$ 18,000
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2019	2,981
2020	11,925
2021	8,083
2022	5,150
2023	3,434
Total finite-lived intangible assets, net	$ 31,573		$ 44,528