Condensed Consolidated Statements Of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Statement [Abstract]
Net revenues	$ 212,609	$ 212,575	$ 581,160	$ 581,462
Cost of sales	157,535	160,582	469,898	473,589
Gross profit	55,074	51,993	111,262	107,873
Gain on disposition of assets, net	0	146	0	146
Selling, general and administrative expenses	(16,076)	(20,762)	(48,923)	(52,986)
Income from operations	38,998	31,377	62,339	55,033
Equity in losses of investment	(13)	(107)	(82)	(378)
Net interest expense	(1,901)	(3,249)	(6,204)	(10,744)
Loss on extinguishment of long-term debt	0	(2)	(18)	(1,183)
Other expense, net	(2,285)	(709)	(2,430)	(3,225)
Royalty income and other	362	652	2,897	4,068
Income before income taxes	35,161	27,962	56,502	43,571
Income tax provision	3,539	841	6,739	1,226
Net income	31,622	27,121	49,763	42,345
Net loss attributable to redeemable noncontrolling interests	(73)	0	(104)	0
Net income attributable to common shareholders	$ 31,695	$ 27,121	$ 49,867	$ 42,345
Earnings per share of common stock (in dollars per share)
Basic	$ 0.21	$ 0.18	$ 0.33	$ 0.29
Diluted	$ 0.21	$ 0.18	$ 0.33	$ 0.29
Weighted average common shares outstanding (in shares)
Basic	147,575	146,700	147,506	146,679
Diluted	148,354	146,964	148,086	146,761