Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Income Statement [Abstract]
Net sales:	$ 266,036	$ 247,627	$ 481,373	$ 454,232
Cost of sales	195,533	185,802	362,552	343,152
Gross profit	70,503	61,825	118,821	111,080
Selling, general, and administrative expense	38,229	36,895	72,704	76,471
Income from operations	32,274	24,930	46,117	34,609
Interest expense	3,130	3,550	6,399	7,126
Other expense (income)	13	353	(572)	407
Income before taxes	29,131	21,027	40,290	27,076
Provision for income taxes	6,294	7,853	9,101	9,906
Income from continuing operations	22,837	13,174	31,189	17,170
Discontinued operations:
Loss before taxes	0	(644)	0	(644)
Benefit of income taxes	0	(239)	0	(239)
Loss from discontinued operations	0	(405)	0	(405)
Net income	$ 22,837	$ 12,769	$ 31,189	$ 16,765
Net earnings per share – Basic:
Income from continuing operations - Net earnings per share - Basic (in USD per share)	$ 0.72	$ 0.41	$ 0.98	$ 0.54
Income from discontinued operations - Net earnings per share - Basic (in USD per share)	0.00	(0.01)	0.00	(0.01)
Net earnings per share - Basic (in USD per share)	0.72	0.40	0.98	0.53
Net earnings per share - Diluted
Income from continuing operations - Net earnings per share - Diluted (in USD per share)	0.70	0.41	0.96	0.53
Income from discontinued operations - Net earnings per share - Diluted (in USD per share)	0.00	(0.01)	0.00	(0.01)
Net earnings per share - Diluted (in USD per share)	$ 0.70	$ 0.40	$ 0.96	$ 0.52
Weighted Average Number of Shares Outstanding
Weighted average basic shares outstanding (in shares)	31,862	31,709	31,824	31,698
Weighted average shares outstanding, diluted (in shares)	32,553	32,183	32,498	32,219