Note 15 - Stock-based Compensation - Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Expense	$ 843	$ 876	$ 2,636	$ 2,732
Deferred tax benefit	(179)	(209)	(552)	(573)
Total net expense	664	667	2,084	2,159
Stock Appreciation Rights (SARs) [Member]
Expense	88	88	265	258
Deferred tax benefit	(19)	(18)	(56)	(54)
Total net expense	69	70	209	204
Restricted Stock [Member]
Expense	424	292	1,064	891
Deferred tax benefit	(90)	(65)	(223)	(186)
Total net expense	334	227	841	705
Restricted Stock Units (RSUs) [Member]
Expense	67	82	202	246
Deferred tax benefit	(14)	(17)	(42)	(52)
Total net expense	53	65	160	194
Performance Shares [Member]
Expense	264	414	1,105	1,337
Deferred tax benefit	(56)	(109)	(231)	(281)
Total net expense	$ 208	$ 305	$ 874	$ 1,056