Note 19 - Segments - Reconciliation of Segment EBITDA to Consolidated Net Income (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Segment EBITDA	$ 234,000	$ (3,000)		$ 469,000	$ 203,000
Corporate expense and other items, net	(1,000)	(2,000)		(2,000)	(3,000)
Depreciation	(92,000)	(84,000)		(180,000)	(169,000)
Amortization	(5,000)	(5,000)		(12,000)	(9,000)
Non-service cost components of pension and OPEB costs	(3,000)	(3,000)		(5,000)	(5,000)
Restructuring charges, net	0	(16,000)		(1,000)	(19,000)
Stock compensation expense	(4,000)	1,000		(9,000)	(3,000)
Strategic transaction expenses	(5,000)	(5,000)		(8,000)	(11,000)
Gain (loss) on investment in Hyliion	3,000			(14,000)		$ 33,000
Impairment of goodwill			$ (51,000)		(51,000)
Loss on disposal group held for sale				(7,000)
Loss on de-designation of fixed-to-fixed cross currency swaps	(9,000)			(9,000)
Other items	(5,000)	5,000		(1,000)	2,000
Earnings (loss) before interest and income taxes	113,000	(112,000)		221,000	(65,000)
Loss on extinguishment of debt	(24,000)	(5,000)		(24,000)	(5,000)
Interest income	2,000	2,000		4,000	4,000
Interest expense	34,000	32,000		68,000	61,000
Earnings (loss) before income taxes	57,000	(147,000)		133,000	(127,000)
Income tax expense	14,000	34,000		36,000	18,000
Equity in earnings of affiliates	10,000	8,000		24,000	10,000
Net income (loss)	$ 53,000	$ (173,000)		$ 121,000	$ (135,000)