Consolidated Statement of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement [Abstract]
Net sales	$ 877,140	$ 817,740	$ 794,020
Cost of sales	(633,020)	(598,350)	(583,220)
Gross profit	244,120	219,390	210,800
Selling, general and administrative expenses	(121,800)	(129,140)	(151,960)
Net loss on dispositions of assets	(250)	(1,080)	(1,870)
Impairment of goodwill and indefinite-lived intangible assets	0	0	(98,900)
Operating profit (loss)	122,070	89,170	(41,930)
Other expense, net:
Interest expense	(13,910)	(14,400)	(13,720)
Debt financing and related expenses	0	(6,640)	0
Other expense, net	(2,180)	(1,920)	(2,580)
Other expense, net	(16,090)	(22,960)	(16,300)
Income (loss) before income taxes	105,980	66,210	(58,230)
Income tax benefit (expense)	(22,680)	(35,250)	18,430
Net income (loss)	$ 83,300	$ 30,960	$ (39,800)
Basic earnings (loss) per share:
Net income (loss) per share	$ 1.82	$ 0.68	$ (0.88)
Weighted average common shares—basic	45,824,555	45,682,627	45,407,316
Diluted earnings (loss) per share:
Net income (loss) per share	$ 1.80	$ 0.67	$ (0.88)
Weighted average common shares—diluted	46,170,464	45,990,252	45,407,316