Note 17 - Segment Information - Segment Reporting Information by Revenue (Details) - USD ($) $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2019		Sep. 30, 2019		Jun. 30, 2019		Mar. 31, 2019		Dec. 31, 2018		Sep. 30, 2018		Jun. 30, 2018		Mar. 31, 2018		Dec. 31, 2019		Dec. 31, 2018		Dec. 31, 2017
Net sales	$ 319,740		$ 384,230		$ 429,151		$ 445,919		$ 429,590		$ 456,976		$ 452,917		$ 375,598		$ 1,579,040		$ 1,715,081		$ 1,330,696
Depreciation and amortization																	19,030		17,608		17,478
Operating income	$ 1,015	[1]	$ 3,581	[1]	$ 5,940	[1]	$ 6,074	[1]	$ 1,774	[2]	$ 18,614	[2]	$ 24,319	[2]	$ 12,345	[2]	16,610	[1]	57,052	[2]	23,986
Other loss, net																	(32)		(307)		(118)
Income before interest and income taxes																	16,578		56,745		23,868
Interest and other expense on debt																	11,289		10,681		7,518
Income before income taxes																	5,289		46,064		16,350
Carbon Flat Products [Member]
Net sales																	926,903		1,073,292		869,628
Depreciation and amortization																	11,624		10,621		10,906
Operating income																	(5,023)		44,354		17,886
Specialty Metals Flat Products [Member]
Net sales																	363,634		343,479		227,200
Depreciation and amortization																	1,830		1,251		811
Operating income																	14,321		15,248		11,240
Tubular and Pipe Products [Member]
Net sales																	288,503		298,310		233,868
Depreciation and amortization																	5,408		5,601		5,659
Operating income																	18,607		11,520		4,568
Corporate Segment [Member]
Depreciation and amortization																	168		135		102
Operating income																	$ (11,295)		$ (14,070)		$ (9,708)

[1] Operating income (loss) in 2019 includes $3,669 of LIFO income related to the Company's tubular and pipe products segment.

[2] Operating income (loss) in 2018 includes $8,408 of LIFO expense related to the Company's tubular and pipe products segment.