Condensed Consolidated Statements Of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Statement [Abstract]
Net revenues	$ 201,728	$ 204,625	$ 368,551	$ 368,887
Cost of sales	161,794	161,728	312,363	313,007
Gross profit	39,934	42,897	56,188	55,880
Selling, general and administrative expenses	(16,862)	(18,125)	(32,847)	(32,224)
Income from operations	23,072	24,772	23,341	23,656
Equity in losses of investment	(29)	(135)	(69)	(271)
Net interest expense	(2,205)	(3,599)	(4,303)	(7,495)
Loss on extinguishment of long-term debt	(18)	(76)	(18)	(1,181)
Other expense, net	(1,311)	(3,441)	(145)	(2,516)
Royalty income and other	190	561	2,535	3,416
Income before income taxes	19,699	18,082	21,341	15,609
Income tax provision	2,876	298	3,200	385
Net income	16,823	17,784	18,141	15,224
Net loss attributable to redeemable noncontrolling interests	(31)	0	(31)	0
Net income attributable to common shareholders	$ 16,854	$ 17,784	$ 18,172	$ 15,224
Earnings per share of common stock (in dollars per share)
Basic	$ 0.11	$ 0.12	$ 0.12	$ 0.10
Diluted	$ 0.11	$ 0.12	$ 0.12	$ 0.10
Weighted average common shares outstanding (in shares)
Basic	147,521	146,683	147,471	146,668
Diluted	148,101	146,724	147,931	146,668