LEASES: Lease Cost (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Mar. 31, 2019
Lessee, Lease, Description [Line Items]
Right-of-use asset (see Note 2)	$ 17,830	$ 0
Other Noncurrent Assets
Lessee, Lease, Description [Line Items]
Right-of-use asset (see Note 2)	17,800
Accrued Liabilities
Lessee, Lease, Description [Line Items]
Short-term lease liabilities (See Note 2)	9,641	$ 0
Other Noncurrent Liabilities
Lessee, Lease, Description [Line Items]
Long-term lease liabilities	$ 11,400