OTHER CURRENT AND NONCURRENT ASSETS: (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Mar. 31, 2019
Other current assets
Prepaid expenses and other	$ 8,108	$ 9,058
Other Receivables	17,625	17,625
Interest Receivable	1,921	2,497
Assets of non-qualified retirement plan	15,263	14,970
Other current assets	42,917	44,150
Other noncurrent assets
Acquired intangible assets, net	22,054	24,217
Operating lease, right-of-use asset	20,930	0
Other miscellaneous noncurrent assets	8,025	8,282
Other assets, net	$ 51,009	$ 32,499