Note 9 - Income Taxes Income Tax (Details) $ in Millions	Mar. 31, 2018 USD ($)
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	$ 8.4
Operating Loss Carryforwards Due to Acquisitions	2.3
Deferred Tax Assets, Tax Credit Carryforwards, Research	6.8
Deferred Tax Assets, Tax Credit Carryforwards, Alternative Minimum Tax	57.1
State and Local NOL Carryforwards [Member]
Operating Loss Carryforwards [Line Items]
Valuation Allowance, Amount	$ 64.4