Note 9 - Pension Plans - Net Periodic Pension Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Service cost	$ 109	$ 101	$ 104
Interest cost	1,313	1,450	1,803
Expected return on plan assets	(1,183)	(1,721)	(1,910)
Recognized actuarial loss	387	438	179
Net periodic pension expense	$ 626	$ 268	$ 176