Note 10 - Business Segments - Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Assets	$ 5,779,062	$ 5,470,854
Operating Segments [Member] | JBI [Member]
Assets	2,462,000	2,217,000
Operating Segments [Member] | DCS [Member]
Assets	1,529,000	1,445,000
Operating Segments [Member] | ICS [Member]
Assets	268,000	208,000
Operating Segments [Member] | FMS [Member]
Assets	433,000	432,000
Operating Segments [Member] | JBT [Member]
Assets	267,000	241,000
Segment Reconciling Items [Member]
Assets	$ 820,000	$ 928,000