Note 15 - Accumulated Other Comprehensive Loss - Changes in Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2019	Mar. 31, 2019
Balance	$ 680,251	$ 640,093
Balance	704,154	680,251
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]
Balance	(812)	(1,638)
Other comprehensive income before reclassifications	675	924
Tax effect	(64)	(98)
Other comprehensive income	611	826
Balance	(201)	(812)
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Balance	(228)	(3,905)
Other comprehensive income before reclassifications	(3,709)	3,677
Tax effect	0	0
Other comprehensive income	(3,709)	3,677
Balance	(3,937)	(228)
AOCI Attributable to Parent [Member]
Balance	(1,040)	(5,543)
Other comprehensive income before reclassifications	(3,034)	4,601
Tax effect	(64)	(98)
Other comprehensive income	(3,098)	4,503
Balance	$ (4,138)	$ (1,040)