Selected Quarterly Financial Data (Unaudited) (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Revenues	$ 252,828	$ 237,835	$ 157,785	$ 214,010	$ 264,865	$ 233,590	$ 238,263	$ 218,378	$ 862,459	$ 955,097	$ 859,634
Gross Profit	135,514	133,698	71,929	119,159	141,975	130,111	131,190	121,438	460,300	524,715	469,110
Net income	24,140	6,850	(27,400)	5,927	14,933	6,970	5,695	1,021	9,517	28,620	40,854
Acquisition and integration costs	600	800	1,100	1,600	1,900	1,700	$ 3,000	7,900			1,100
Restructuring And Related Costs	$ 1,600	1,000	3,200
Manufacturing consolidation costs		$ 600	1,600	$ 1,800	$ 1,400	$ 1,400
Other expense								$ 3,900	355	5,188	0
Plant underutilization cost			6,600
Impairment charges									$ 0	$ 312	$ 4,212
Product rationalization costs			$ 4,300
Incremental Common Shares Attributable to Dilutive Effect of Conversion of Debt Securities	0.2	0.2			0.6
EPS:
Basic (in dollars per share)	$ 0.84	$ 0.24	$ (0.96)	$ 0.21	$ 0.53	$ 0.25	$ 0.20	$ 0.04	$ 0.33	$ 1.01	$ 1.45
Diluted (in dollars per share)	$ 0.81	$ 0.23	$ (0.96)	$ 0.20	$ 0.49	$ 0.23	$ 0.19	$ 0.04	$ 0.32	$ 0.97	$ 1.41