Note 10 - Business Segments - Operating Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Operating income	$ 174,688	$ 164,972	$ 558,282	$ 477,976
Corporate and Reconciling Items [Member]
Operating income			(100)
JBI [Member] | Operating Segments [Member]
Operating income	120,300	109,100	368,600	314,100
DCS [Member] | Operating Segments [Member]
Operating income	35,000	42,900	134,000	136,200
ICS [Member] | Operating Segments [Member]
Operating income	10,200	7,300	34,000	11,500
JBT [Member] | Operating Segments [Member]
Operating income	$ 9,200	$ 5,700	$ 21,800	$ 16,200