STOCK-BASED COMPENSATION: Stock-based compensation activity, by award type (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Sep. 30, 2018	Jun. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Share-based compensation
Other non-employee stock-based compensation					$ 600	$ 700
Total non-cash stock-based compensation					42,000	35,500
Stock-based compensation of discontinued operations					0	5,700
Total non-cash stock-based compensation included in the condensed consolidated statement of equity	$ 16,268	$ 15,064	$ 17,281	$ 16,811	31,300	34,100
Cost of revenue
Share-based compensation
Total non-cash stock-based compensation					1,800	1,500
Research and development
Share-based compensation
Total non-cash stock-based compensation					10,000	7,900
Sales and marketing
Share-based compensation
Total non-cash stock-based compensation					18,700	19,800
General and administrative
Share-based compensation
Total non-cash stock-based compensation					11,500	6,300
Stock options
Share-based compensation
Share-based compensation expense					1,800	1,700
Restricted stock units
Share-based compensation
Share-based compensation expense					25,400	17,500
Arbor Holdback Agreement | Arbor
Share-based compensation
Share-based compensation expense					2,600	7,700
Consideration Holdback | Data Plus Math Corporation
Share-based compensation
Share-based compensation expense					2,100	0
Pacific Data Partners, LLC Agreement Plan | Pacific Data Partners LLC
Share-based compensation
Share-based compensation expense					9,500	7,900
Liability-based equity awards
Share-based compensation
Total non-cash stock-based compensation					$ (10,700)	$ (7,100)