REVENUE FROM CONTRACTS WITH CUSTOMERS: Transaction Price Allocated to the Remaining Performance Obligations (Details) $ in Millions	Mar. 31, 2021 USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 371.0
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 255.8
Revenue, remaining performance obligation, expected timing of satisfaction, period	12 months