Note 9 - Pension Plans - Net Amount Recognized (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2017	Mar. 31, 2016
Change in projected benefit obligation:
Projected benefit obligation at the beginning of the year	$ 45,021	$ 47,346
Service cost	109	101	$ 104
Interest cost	1,313	1,450	1,803
Actuarial (gain) loss	3,356	(1,549)
Benefits paid	(1,543)	(1,830)
Foreign currency adjustment	(5,073)	(497)
Projected benefit obligation at year end	43,183	45,021	47,346
Change in plan assets:
Fair value of plan assets at the beginning of the year	28,714	30,114
Actual return (loss) on plan assets	3,526	(156)
Employer contribution	993	1,009
Benefits paid from assets	(1,083)	(1,388)
Foreign currency adjustment	(3,868)	(865)
Plan assets at fair value at year end	28,282	28,714	30,114
Unfunded status of the plan at year end				$ 14,901	$ 16,307
Pension liability recognized on the balance sheet due after one year				14,901	16,307
Plans with projected benefit obligation and accumulated benefit obligation in excess of plan assets:
Projected benefit obligation at year end				43,183	45,021
Accumulated benefit obligation at year end				42,652	44,509
Plan assets at fair value at year end	$ 28,714	$ 28,714	$ 30,114	28,282	28,714
Amounts recognized in accumulated other comprehensive income (loss):
Unrecognized actuarial loss, before tax				(11,457)	(12,140)
Amount recognized as component of stockholders’ equity – pretax				(11,457)	(12,140)
Accumulated benefit obligation at year end				$ 42,652	$ 44,509