DISCONTINUED OPERATIONS: Reconciliation of the major classes of line items constituting earnings from discontinued operations (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income taxes									$ 207	$ 470,346	$ 42,952
Earnings from discontinued operations, net of tax	$ 750	$ 0	$ 0	$ 0	$ 4,227	$ 1,071,661	$ 61,803	$ 24,803	750	$ 1,162,494	90,779
Acxiom Marketing Solutions | Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues					332,185				0		697,305
Costs of revenues					213,512				0		370,040
Gross profit					118,673				0		327,265
Research and development					21,621				0		34,160
Sales and marketing					60,743				0		106,960
General and administrative					71,500				0		38,372
Gains, losses and other items, net					(1,673,636)				(957)		3,650
Total operating expense					(1,519,772)				(957)		183,142
Income from discontinued operations					1,638,445				957		144,123
Interest expense					(5,702)				0		(10,131)
Other, net					97				0		(261)
Earnings from discontinued operations before income taxes					1,632,840				957		133,731
Income taxes					470,346				207		42,952
Earnings from discontinued operations, net of tax					$ 1,162,494				$ 750		$ 90,779