REVENUE FROM CONTRACTS WITH CUSTOMERS: Disaggregation of Revenue (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
Disaggregation of Revenue [Line Items]
Revenues	$ 105,701	$ 102,217	$ 90,143	$ 82,511	$ 78,316	$ 80,021	$ 64,812	$ 62,471	$ 380,572	$ 285,620	$ 220,101
Subscription
Disaggregation of Revenue [Line Items]
Revenues									305,679	236,718	172,079
Marketplace and Other
Disaggregation of Revenue [Line Items]
Revenues									74,893	48,902	48,022
United States
Disaggregation of Revenue [Line Items]
Revenues									354,437	262,135	197,613
Europe
Disaggregation of Revenue [Line Items]
Revenues									20,789	18,566	18,397
APAC
Disaggregation of Revenue [Line Items]
Revenues									$ 5,346	$ 4,919	$ 4,091