Note 13 - Recently Issued Accounting Pronouncements (Details Textual) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Dec. 30, 2018
Operating Lease, Right-of-Use Asset	$ 113,640		$ 0
Operating Lease, Liability, Total	$ 113,330
Accounting Standards Update 2016-02 [Member]
Operating Lease, Right-of-Use Asset		$ 115,000
Operating Lease, Liability, Total		$ 115,000