OTHER ACCRUED EXPENSES: (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Mar. 31, 2019
Lessee, Lease, Description [Line Items]
Liabilities of non-qualified retirement plan	$ 11,623	$ 14,970
PDP performance plan liability (see Note 13)	16,318	0
DPM consideration holdback (see Note 13)	6,185	0
Other miscellaneous accrued expenses	25,224	25,946
Other accrued expenses	68,991	40,916
Accrued Liabilities
Lessee, Lease, Description [Line Items]
Short-term lease liabilities (See Note 2)	$ 9,641	$ 0