Revenue Recognition (Impact of New Revenue Guidance on Statements of Operations) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	$ 151,825	$ 124,832	$ 163,446	$ 83,964	$ 137,969	$ 125,339	$ 139,371	$ 72,248	$ 524,067	$ 474,927	$ 416,268
Cost of sales									369,177	331,841	282,294
Gross profit	44,094	34,920	55,849	20,027	44,811	36,055	45,033	17,187	154,890	143,086	133,974
Selling, general, and administrative expense									69,958	60,877	53,570
Intangibles amortization									11,472	11,401	10,596
Income from operations									73,460	70,808	69,808
Interest expense, net									(16,943)	(18,336)	(15,195)
Other expense, net									(758)	(832)	(967)
Income before taxes	$ 19,748	$ 11,069	$ 28,080	$ (3,138)	$ 21,451	$ 15,081	$ 22,354	$ (5,971)	55,759	52,915	63,696
Income tax expense (benefit)									11,854	(2,409)	24,687
Net income									$ 43,905	$ 55,324	$ 39,009
Loss per common share:
Basic (in dollars per share)	$ 0.64	$ 0.43	$ 0.92	$ (0.08)	$ 1.51	$ 0.41	$ 0.64	$ (0.14)	$ 1.91	$ 2.42	$ 1.71
Diluted (in dollars per share)	$ 0.63	$ 0.43	$ 0.91	$ (0.08)	$ 1.50	$ 0.40	$ 0.64	$ (0.14)	$ 1.89	$ 2.40	$ 1.70
ASC 2014-09 | Balances without adoption of Topic 606
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Net sales									$ 523,768
Cost of sales									368,913
Gross profit									154,855
Income from operations									73,425
Income tax expense (benefit)									11,845
Net income									43,879
ASC 2014-09 | Effect of Change Higher/(Lower)
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Net sales									299
Cost of sales									264
Gross profit									35
Income from operations									35
Income tax expense (benefit)									9
Net income									$ 26
Loss per common share:
Basic (in dollars per share)									$ 1.91
Diluted (in dollars per share)									$ 1.89