Note 11 - Accumulated Other Comprehensive Income (Loss) - AOCI Change (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Balance, Beginning of Period	$ 297,855
Balance, End of Period	315,216
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Balance, Beginning of Period	(19,233)	$ (10,639)
Other comprehensive income (loss) before reclassifications	6,882	(2,825)
Net loss reclassified from accumulated other comprehensive income (loss)
Other Comprehensive Income (Loss)	6,882	(2,825)
Balance, End of Period	(12,351)	(13,464)
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Balance, Beginning of Period	(219)	(82)
Other comprehensive income (loss) before reclassifications	(13)	85
Net loss reclassified from accumulated other comprehensive income (loss)		90
Other Comprehensive Income (Loss)	(13)	175
Balance, End of Period	(232)	93
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Balance, Beginning of Period	(9,093)	(9,545)
Other comprehensive income (loss) before reclassifications
Net loss reclassified from accumulated other comprehensive income (loss)
Other Comprehensive Income (Loss)
Balance, End of Period	(9,093)	(9,545)
AOCI Attributable to Parent [Member]
Balance, Beginning of Period	(28,545)	(20,266)
Other comprehensive income (loss) before reclassifications	6,869	(2,740)
Net loss reclassified from accumulated other comprehensive income (loss)		90
Other Comprehensive Income (Loss)	6,869	(2,650)
Balance, End of Period	$ (21,676)	$ (22,916)