Note 17 - Stock-based Compensation - Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Expense	$ 3,578	$ 4,027	$ 2,892
Deferred tax benefit	(751)	(846)	(607)
Total net expense	2,827	3,181	2,285
Stock Appreciation Rights (SARs) [Member]
Expense	345	379	280
Deferred tax benefit	(72)	(80)	(59)
Total net expense	273	299	221
Restricted Stock [Member]
Expense	1,185	1,100	1,032
Deferred tax benefit	(249)	(231)	(216)
Total net expense	936	869	816
Restricted Stock Units (RSUs) [Member]
Expense	329	248	219
Deferred tax benefit	(69)	(52)	(46)
Total net expense	260	196	173
Performance Shares [Member]
Expense	1,719	2,300	1,361
Deferred tax benefit	(361)	(483)	(286)
Total net expense	$ 1,358	$ 1,817	$ 1,075