Supplemental Guarantor Financial Information - Condensed Consolidating Statement of Operations and Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Condensed Financial Statements, Captions [Line Items]
Net sales	$ 1,761,500	$ 1,724,200	$ 1,730,400
Cost and expenses:
Cost of sales	(1,597,000)	(1,536,700)	(1,521,200)
Selling, general and administrative expenses	(112,800)	(107,800)	(121,200)
Other Operating Income (Expense), Net	6,300	(17,500)	16,800
Goodwill, Impairment Loss	0	195,100	0
Total operating costs and expenses	1,716,100	1,822,100	1,659,200
Income (loss) from operations	45,400	(97,900)	71,200
Interest Income (Expense), Nonoperating, Net	(44,900)	(30,700)	(31,400)
Debt retirement costs	(2,700)	0	0
Net periodic Defined Benefits Expense (Reversal of Expense), Excluding Service Cost Component	(5,700)	(4,900)	1,100
Earnings before income taxes	(7,900)	(133,500)	40,900
Income tax (provision) benefit	(2,300)	10,300	(56,400)
Equity in income (loss) of subsidiary	0	0	0
Net income (loss)	(5,600)	(143,800)	97,300
Other comprehensive income, net of tax	7,800	(10,500)	7,800
Comprehensive income	2,200	(154,300)	105,100
Gain (Loss) on Disposition of Assets	0	24,000	0
Issuer
Condensed Financial Statements, Captions [Line Items]
Net sales	1,653,100	1,752,300	1,707,300
Cost and expenses:
Cost of sales	(1,510,300)	(1,581,700)	(1,516,500)
Selling, general and administrative expenses	(93,800)	(87,000)	(90,800)
Other Operating Income (Expense), Net	6,300	6,500	16,800
Goodwill, Impairment Loss		195,100
Total operating costs and expenses	1,610,400	1,870,300	1,624,100
Income (loss) from operations	42,700	(118,000)	83,200
Interest Income (Expense), Nonoperating, Net	(44,700)	(30,200)	(30,800)
Debt retirement costs	(2,700)
Net periodic Defined Benefits Expense (Reversal of Expense), Excluding Service Cost Component	(5,700)	(4,900)	1,100
Earnings before income taxes	(10,400)	(153,100)	53,500
Income tax (provision) benefit	(7,700)	5,200	(34,300)
Equity in income (loss) of subsidiary	3,800	18,300	11,900
Net income (loss)	1,100	(140,000)	99,700
Other comprehensive income, net of tax	7,800	(10,500)	7,800
Comprehensive income	8,900	(150,500)	107,500
Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net sales	268,300	194,900	242,200
Cost and expenses:
Cost of sales	(243,900)	(173,000)	(219,900)
Selling, general and administrative expenses	(19,000)	(20,800)	(30,400)
Other Operating Income (Expense), Net	0	(24,000)	0
Goodwill, Impairment Loss		0
Total operating costs and expenses	262,900	169,800	250,300
Income (loss) from operations	5,400	25,100	(8,100)
Interest Income (Expense), Nonoperating, Net	(200)	(500)	(600)
Debt retirement costs	0
Net periodic Defined Benefits Expense (Reversal of Expense), Excluding Service Cost Component	0	0	0
Earnings before income taxes	5,200	24,600	(8,700)
Income tax (provision) benefit	1,400	6,300	(20,600)
Equity in income (loss) of subsidiary	0	0	0
Net income (loss)	3,800	18,300	11,900
Other comprehensive income, net of tax	0	0	0
Comprehensive income	3,800	18,300	11,900
Eliminations
Condensed Financial Statements, Captions [Line Items]
Net sales	(159,900)	(223,000)	(219,100)
Cost and expenses:
Cost of sales	157,200	218,000	215,200
Selling, general and administrative expenses	0	0	0
Other Operating Income (Expense), Net	0	0	0
Goodwill, Impairment Loss		0
Total operating costs and expenses	(157,200)	(218,000)	(215,200)
Income (loss) from operations	(2,700)	(5,000)	(3,900)
Interest Income (Expense), Nonoperating, Net	0	0	0
Debt retirement costs	0
Net periodic Defined Benefits Expense (Reversal of Expense), Excluding Service Cost Component	0	0	0
Earnings before income taxes	(2,700)	(5,000)	(3,900)
Income tax (provision) benefit	4,000	(1,200)	(1,500)
Equity in income (loss) of subsidiary	(3,800)	(18,300)	(11,900)
Net income (loss)	(10,500)	(22,100)	(14,300)
Other comprehensive income, net of tax	0	0	0
Comprehensive income	$ (10,500)	$ (22,100)	$ (14,300)