Note 12 - Federal and State Income Taxes - Income Tax Rate Reconciliation (Details) - USD ($) $ in Thousands			3 Months Ended								12 Months Ended
		Dec. 21, 2017	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income tax at the statutory federal rate, amount											$ 2,124	$ 6,582	$ 4,975
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent		35.00%									21.00%	21.00%	34.00%
Impact of the Tax Cuts and Jobs Act, amount	[1]												$ (29,255)
Impact of the Tax Cuts and Jobs Act, percent	[1]												(199.90%)
Nondeductible expenses, amount											$ 342	$ 80	$ 72
Nondeductible expenses, percent											3.40%	0.20%	0.50%
State income taxes/other—net of federal benefit, amount											$ (251)	$ 685	$ (60)
State income taxes/other—net of federal benefit, percent											(2.50%)	2.20%	(0.50%)
Total income tax provision (benefit) expense			$ (4,168)	$ 1,264	$ 2,301	$ 2,818	$ 1,883	$ 3,129	$ 2,005	$ 330	$ 2,215	$ 7,347	$ (24,268)
Total income tax (benefit) expense, percent											21.90%	23.40%	(165.90%)

[1] On December 22, 2017, the Tax Cuts and Jobs Act (the “Act”) was signed into law. The Act included numerous changes to existing tax law, including a permanent reduction in the federal corporate income tax rate from 35% to 21% effective January 1, 2018 and repeal of the alternative minimum tax (“AMT”) allowing a refund of existing AMT carryovers during the years 2018 through 2021. As a result, the Company recorded a tax benefit of $29.3 million in the fourth quarter of 2017 related to the revaluation of its net deferred tax liabilities.