Note 9 - Income Taxes Income Tax (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards, State and Local, Net of Federal Benefit	$ 68.0
US Treasury Securities
Operating Loss Carryforwards [Line Items]
Debt Securities	89.2
Internal Revenue Service (IRS)
Operating Loss Carryforwards [Line Items]
Income Taxes Payable, Federal, Current	33.4
REMIC Residual | Internal Revenue Service (IRS)
Operating Loss Carryforwards [Line Items]
Qualified Deposit Assets With The U.S. Department Of Treasury Expected to be Submitted		$ 31.0
Refund of Qualified Deposit Assets from U.S. Department of Treasury		$ 57.2
State and Local NOL Carryforwards
Operating Loss Carryforwards [Line Items]
Valuation Allowance, Amount	$ 67.9