Note 1 - Summary of Significant Accounting Policies (Details Textual) $ in Thousands	Jan. 01, 2019 USD ($)	Jun. 30, 2019 USD ($)	Dec. 31, 2018
Number Of Wholly Owned Trusts		1	1
Operating Lease, Right-of-Use Asset		$ 3,569
Operating Lease, Right-of-use Assets, Reduction for Amounts Recognized Previously	$ 458
Operating Lease, Liability, Total		$ 3,994
Accounting Standards Update 2016-02 [Member]
Operating Lease, Right-of-Use Asset	4,400
Operating Lease, Liability, Total	$ 4,400