Note 9 - Income Taxes Summary of Income Tax Examinations (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Jun. 30, 2018	Sep. 30, 2018	Dec. 31, 2017
Income Tax Examination [Line Items]
Deferred Tax Assets, Tax Credit Carryforwards, Alternative Minimum Tax		$ 7,000
Deposit Assets		88,557	$ 88,557
Internal Revenue Service (IRS)
Income Tax Examination [Line Items]
Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities		88,600
REMIC Residual | Internal Revenue Service (IRS)
Income Tax Examination [Line Items]
Income Tax Expense (Benefit) Recorded as a Result of Finalized IRS Settlement	$ (73,600)
Qualified Deposit Assets With The U.S. Department Of Treasury Expected to be Submitted		31,000
Deposit Assets		89,000
State and Local NOL Carryforwards [Member]
Income Tax Examination [Line Items]
Deferred Tax Assets, Valuation Allowance		$ 53,100