Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Income Statement [Abstract]
Net sales	$ 426,186	$ 410,219	$ 757,062	$ 702,077
Cost of goods sold	320,607	324,405	592,741	574,458
Gross profit	105,579	85,814	164,321	127,619
Selling, general & administrative expenses	(53,283)	(58,640)	(107,523)	(110,031)
Impairment and exit charges	(265)	(582)	(1,089)	(813)
Other operating (loss) income, net	(1,001)	(376)	(671)	203
Operating expenses	(54,549)	(59,598)	(109,283)	(110,641)
Income from operations	51,030	26,216	55,038	16,978
Other income (expense)
Interest expense	(19,702)	(25,783)	(40,447)	(50,448)
Gain on extinguishment of debt	116	0	66	0
Earnings from equity method investee	3,126	3,402	5,925	4,969
Income (loss) before income taxes	34,570	3,835	20,582	(28,501)
Income tax (expense) benefit	(7,455)	(881)	(7,533)	6,416
Net income (loss)	$ 27,115	$ 2,954	$ 13,049	$ (22,085)
Earnings (loss) per share:
Basic (in dollars per share)	$ 0.42	$ 0.05	$ 0.20	$ (0.34)
Diluted (in dollars per share)	$ 0.40	$ 0.05	$ 0.19	$ (0.34)
Weighted average common shares outstanding:
Basic (in shares)	65,093	64,142	64,948	64,073
Diluted (in shares)	67,191	64,464	67,458	64,073