Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended								6 Months Ended		9 Months Ended		12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Total revenues	$ 204,570	$ 149,508	$ 131,065	$ 126,642	$ 198,166	$ 171,301	$ 135,583	$ 125,032	$ 257,707	$ 260,615	$ 407,216	$ 431,916	$ 611,786	$ 630,082	$ 612,056
Cost of sales	162,173	118,562	102,558	99,940	156,173	132,897	104,856	97,104	202,498	201,960	321,060	334,857	483,234	491,030	475,939
Gross profit	42,397	30,946	28,507	26,702	41,993	38,404	30,727	27,928	55,209	58,655	86,155	97,059	128,552	139,052	136,117
Selling, general and administrative expenses	22,996	26,165	24,976	26,246	25,599	26,296	26,437	25,789	51,222	52,225	77,385	78,522	100,381	104,121	96,780
Amortization of intangible assets	341	345	346	345	345	345	346	345	691	691	1,036	1,036	1,377	1,381	1,381
Operating profit	19,060	4,439	3,185	111	16,050	11,763	3,944	1,794	3,296	5,738	7,734	17,501	26,794	33,550	37,956
Interest expense, net	767	756	789	663	711	886	809	510	1,452	1,319	2,208	2,205	2,975	2,916	1,572
Other expense (income), net	(710)	681	(132)	(197)	429	(433)	679	(526)	(329)	153	352	(280)	(358)	149	(692)
Income from continuing operations before income taxes	19,003	3,002	2,528	(355)	14,910	11,310	2,456	1,810	2,173	4,266	5,174	15,576	24,177	30,485	37,076
Income tax expense	5,699	2,449	630	307	3,420	2,280	811	916	937	1,727	3,385	4,007	9,084	7,426	18,967
Net income from continuing operations	13,304	553	1,898	(662)	11,490	9,030	1,645	894	1,236	2,539	1,789	11,569	15,093	23,059	18,109
Loss from discontinued operations, net of tax	(20,608)	(2,753)	(2,516)	(2,723)	2,371	(1,889)	(2,766)	(3,077)	(5,239)	(5,843)	(7,992)	(7,732)	(28,600)	(5,361)	(2,225)
Net income (loss)	$ (7,304)	$ (2,200)	$ (618)	$ (3,385)	$ 13,861	$ 7,141	$ (1,121)	$ (2,183)	$ (4,003)	$ (3,304)	$ (6,203)	$ 3,837	$ (13,507)	$ 17,698	$ 15,884
Earnings Per Share, Basic and Diluted [Abstract]
Basic and diluted earnings per share, continuing operations (in dollars per share)	$ 0.98	$ 0.04	$ 0.14	$ (0.05)	$ 0.84	$ 0.66	$ 0.12	$ 0.07	$ 0.09	$ 0.19	$ 0.13	$ 0.84	$ 1.10	$ 1.68	$ 1.32
Basic and diluted earnings per share, discontinued operations (in dollars per share)	(1.52)	(0.20)	(0.18)	(0.20)	0.17	(0.14)	(0.20)	(0.22)	(0.38)	(0.43)	(0.58)	(0.56)	(2.09)	(0.39)	(0.16)
Basic and diluted earnings per share (in dollars per share)	$ (0.54)	$ (0.16)	$ (0.04)	$ (0.25)	$ 1.01	$ 0.52	$ (0.08)	$ (0.15)	$ (0.29)	$ (0.24)	$ (0.45)	$ 0.28	$ (0.99)	$ 1.29	$ 1.16
Basic weighted average shares outstanding (in shares)	13,518,000	13,579,000	13,813,000	13,786,000	13,714,000	13,704,000	13,695,000	13,683,000	13,800,000	13,689,000	13,726,000	13,694,000	13,690,000	13,699,000	13,673,000
Diluted weighted average shares outstanding (in shares)	13,625,000	13,595,000	13,826,000	13,786,000	13,844,000	13,713,000	13,704,000	13,692,000	13,813,000	13,693,000	13,731,000	13,697,000	13,726,000	13,731,000	13,685,000