EMPLOYEE BENEFIT PLANS: Activity related to options under all plans (Details) - $ / shares	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Number of Shares
Balance, beginning of period	220,654	223,654	424,654
Options exercised	(59,289)	(3,000)	(18,000)
Forfeited	0	0	(29,000)
Expired	(20,000)	0	(154,000)
Balance, end of period	141,365	220,654	223,654
Weighted Average Exercise Price
Balance, beginning of period	$ 4.74	$ 4.73	$ 8
Options exercised	4.13	3.84	3.49
Forfeited	0	0	10
Expired	13.42	0	12.92
Balance, end of period	$ 3.77	$ 4.74	$ 4.73