Note 12 - Pension Plans - Net Benefit Costs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
UNITED STATES
Service cost		$ 33		$ 99
Interest cost	327	352	982	1,056
Expected return on plan assets	(393)	(450)	(1,179)	(1,350)
Recognized actuarial loss	221	286	663	857
Net periodic pension cost	155	221	466	662
Foreign Plan [Member]
Service cost	206	229	633	688
Interest cost	988	1,151	3,058	3,394
Expected return on plan assets	(1,390)	(1,469)	(4,302)	(4,337)
Recognized actuarial loss	243	333	751	983
Net periodic pension cost	$ 47	$ 244	$ 140	$ 728