Note 14 - Accumulated Other Comprehensive Income (Loss) - Changes in Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020
Balance	$ 848,945		$ 773,491
Balance	914,569	$ 848,945
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]
Balance	3,391	(1,518)	135
Other comprehensive income (loss) before reclassifications	(389)	5,386	(1,680)
Amounts reclassified from accumulated other comprehensive income (loss)	(9)	(71)	(28)
Tax effect	30	(406)	55
Net current period other comprehensive income (loss)	(368)	4,909	(1,653)
Balance	3,023	3,391	(1,518)
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Balance	(7,475)	(8,493)	(5,611)
Other comprehensive income (loss) before reclassifications	6,936	1,018	(2,882)
Amounts reclassified from accumulated other comprehensive income (loss)	0	0	0
Tax effect	0	0	0
Net current period other comprehensive income (loss)	6,936	1,018	(2,882)
Balance	(539)	(7,475)	(8,493)
AOCI Attributable to Parent [Member]
Balance	(4,084)	(10,011)	(5,476)
Other comprehensive income (loss) before reclassifications	6,547	6,404	(4,562)
Amounts reclassified from accumulated other comprehensive income (loss)	(9)	(71)	(28)
Tax effect	30	(406)	55
Net current period other comprehensive income (loss)	6,568	5,927	(4,535)
Balance	$ 2,484	$ (4,084)	$ (10,011)