Selected Quarterly Financial and Supplementary Data - Schedule of Quarterly Financial Information (Unaudited) (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
Quarterly Financial Information Disclosure [Abstract]
Gross sales	$ 124,422		$ 104,231		$ 147,214		$ 139,130		$ 175,505		$ 112,233		$ 134,487		$ 103,711
Net revenues	134,332		104,618		152,046		141,097		182,277		112,619		134,554		105,006		$ 532,093	$ 534,456	$ 490,644
Gross profit	48,316		32,725		64,792		50,855		78,926		46,943		57,559		46,875		196,688	230,303	204,388
Income from continuing operations	1,293	[1]	26,815	[1]	40,852	[1]	24,249	[1]	40,249	[2]	17,276	[2]	25,124	[2]	21,115	[2]	93,209	103,764	87,325
(Loss)/income from discontinued operations	(81)	[3]	(86)	[3]	(433)	[3]	(191)	[3]	10	[3]	20	[3]	(94)	[3]	(1,250)	[3]	(791)	(1,314)	(5,647)
Net income	$ 1,212		$ 26,729		$ 40,419		$ 24,058		$ 40,259		$ 17,296		$ 25,030		$ 19,865		$ 92,418	$ 102,450	$ 81,678
Earnings per share of common stock
Basic	$ 0.04	[4]	$ 0.80	[4]	$ 1.23	[4]	$ 0.74	[4]	$ 1.23	[4]	$ 0.53	[4]	$ 0.77	[4]	$ 0.61	[4]	$ 2.78	$ 3.14	$ 2.55
Diluted	$ 0.04	[4]	$ 0.79	[4]	$ 1.21	[4]	$ 0.72	[4]	$ 1.20	[4]	$ 0.52	[4]	$ 0.75	[4]	$ 0.60	[4]	$ 2.75	$ 3.06	$ 2.48
Average shares:
Basic	33,577		33,406		33,085		32,894		32,810		32,749		32,629		32,454		33,243	32,662	32,086
Diluted	33,815		33,892		33,642		33,621		33,532		33,512		33,469		33,365		33,665	33,486	32,969

[1] Income from continuing operations includes a benefit of approximately $11,400 in the third quarter of 2018 for the release of valuation allowance against state NOLs. A similar amount was recorded as an expense in the fourth quarter of 2018 as a valuation allowance against state NOLs for a change in enacted tax laws. The Company adopted ASC 606 – Revenue from Contracts with Customers on January 1, 2018 using the modified retrospective method which does not require comparative periods, reported under ASC 605, to be restated.

[2] Income from continuing operations includes expense of $117 in the fourth quarter of 2017 as a result of the change in enacted tax rates in the U.S. and the toll tax.

[3] Discontinued operations include charges and reimbursements for environmental remediation related to sites of divested businesses

[4] Earnings per share calculations for each of the quarters are based on the weighted average number of shares outstanding for each period. As such, the sum of the quarters may not necessarily equal the earnings per share amount for the year