Note 1 - Business and Summary of Significant Accounting Policies (Details Textual) $ in Thousands	Mar. 31, 2019 USD ($)	Jan. 01, 2019 USD ($)	Dec. 31, 2018 USD ($)
Number of Businesses	1
Operating Lease, Right-of-Use Asset	$ 20,110
Operating Lease, Liability, Total	$ 24,924
Accounting Standards Update 2016-02 [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption		$ 0
Operating Lease, Right-of-Use Asset		21,300
Operating Lease, Liability, Total		$ 26,300