ALLOWANCE FOR CREDIT LOSSES: Summary of the activity of the allowance for doubtful accounts, returns and credits (Details) - USD ($) $ in Thousands	6 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 7,575
Provision for doubtful accounts	2,522	$ 2,430
Other changes	56
Bad debts written off, net of amounts recovered	(1,141)
Balance at end of period	$ 9,012