Note 8 - Income Taxes (Details Textual) - USD ($)		3 Months Ended			6 Months Ended		12 Months Ended
	Jan. 01, 2018	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018	Sep. 30, 2018	Dec. 31, 2017
Income Tax Expense (Benefit), Total		$ 1,717,000		$ (100,000)	$ (6,600,000)	$ (16,950,000)
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest, Total					$ (23,115,000)	$ (2,443,000)
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%						24.28%	35.00%
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability							$ (16,000,000)
Income Tax Expense (Benefit), Continuing Operations, Revaluation Differences in Deferred Taxes							$ (20,000,000)
Effective Income Tax Rate Reconciliation, Percent, Total					29.00%	694.00%
Domestic Tax Authority [Member] | Earliest Tax Year [Member]
Open Tax Year			2015
State and Local Jurisdiction [Member] | Earliest Tax Year [Member]
Open Tax Year			2013