Note 10 - Business Segments - Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Assets	$ 6,162,606	$ 5,928,348
Operating Segments [Member] | JBI [Member]
Assets	2,579,000	2,426,000
Operating Segments [Member] | DCS [Member]
Assets	1,571,000	1,482,000
Operating Segments [Member] | ICS [Member]
Assets	326,000	301,000
Operating Segments [Member] | FMS [Member]
Assets	491,000	486,000
Operating Segments [Member] | JBT [Member]
Assets	311,000	286,000
Segment Reconciling Items [Member]
Assets	$ 885,000	$ 947,000