OTHER ACCRUED EXPENSES: (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Mar. 31, 2020
Business Acquisition [Line Items]
Liabilities of non-qualified retirement plan	$ 15,838	$ 11,623
Accrued Data Marketplace expenses	15,818	12,023
Short-term lease liabilities (see Note 3)	9,608	9,641
Other miscellaneous accrued expenses	8,034	13,201
Other accrued expenses	58,353	68,991
Pacific Data Partners LLC
Business Acquisition [Line Items]
Business combination, contingent consideration, liability	0	16,318
Other accrued expenses	0
Data Plus Math Corporation
Business Acquisition [Line Items]
Business combination, contingent consideration, liability	6,092	6,185
Acuity Data
Business Acquisition [Line Items]
Business combination, contingent consideration, liability	2,208	0
DataFleets, Ltd
Business Acquisition [Line Items]
Business combination, contingent consideration, liability	$ 755	$ 0