Note 15 - Segment Information - Total Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019	Jun. 30, 2019
Segment Assets	$ 2,566,132	$ 2,693,802	$ 2,765,471
Cash and Other Investments	45,834		183,899
Deferred Tax Assets	108,898	$ 103,505	91,837
Operating Segments [Member] | Reportable Segments [Member]
Segment Assets	1,889,557		1,973,627
Operating Segments [Member] | All Other Segment [Member]
Segment Assets	$ 521,843		$ 516,108