Note 13 - Income Taxes (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2016
New Tax Law, Provisional Income Tax Benefit		$ 3,700
Income Tax Expense (Benefit), Total	$ (1,632)	$ (11,672)		$ 1,844
Effective Income Tax Rate Reconciliation, Percent, Total	2.40%	18.60%	14.70%	14.70%
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability		$ (6,600)
Income Tax Expense (Benefit), Use of Naked Credit as a Source of Income to Release a Portion of Valuation Allowance		(4,800)
Income Tax Expense (Benefit), Refundable AMT Credit		(200)
Deferred Tax Liabilities, Net, Total	$ 28	1,575
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued, Total	0	0	$ 0	$ 0
Tax Credit Carryforward, Amount	36,100
Liability for Uncertainty in Income Taxes	0	0
Domestic Tax Authority [Member] | Internal Revenue Service (IRS) [Member]
Operating Loss Carryforwards, Total	712,700
Operating Loss Carryforwards with Expiration Date		$ 664,100
Operating Loss Carryforwards with Indefinite Term	48,600
State and Local Jurisdiction [Member]
Operating Loss Carryforwards with Expiration Date	577,300
Operating Loss Carryforwards with Indefinite Term	$ 10,300