Selected Quarterly Financial and Supplementary Data (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended																12 Months Ended
	Dec. 31, 2012		Sep. 30, 2012		Jun. 30, 2012		Mar. 31, 2012		Dec. 31, 2011		Sep. 30, 2011		Jun. 30, 2011		Mar. 31, 2011		Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Summary of selected quarterly financial and supplementary data [Abstract]
Gross Sales	$ 70,389		$ 59,841		$ 77,142		$ 70,559		$ 67,134		$ 58,203		$ 67,484		$ 61,654		$ 277,931	$ 254,475	$ 226,436
Net revenues	69,930		59,210		77,133		70,228		67,531		59,155		68,382		60,585		276,501	255,653	226,992
Gross profit	21,083		18,531		28,445		22,428		19,743		17,829		19,057		17,455		90,487	74,084	66,866
Income from continuing operations	44,242	[1]	2,021		9,928		7,038		3,029		3,094		4,757		2,855		63,229	13,735	9,309
(Loss)/income from discontinued operations	(594)	[2]	(332)	[2]	0	[2]	0	[2]	(2,288)	[2]	(333)	[2]	0	[2]	(146)	[2]	(926)	(2,767)	338
Net income	43,648		1,689		9,928		7,038		741		2,761		4,757		2,709		62,303	10,968	9,647
Earnings per share of common stock [Abstract]
Basic (in dollars per share)	$ 1.46	[1],[3]	$ 0.06	[3]	$ 0.34	[3]	$ 0.24	[3]	$ 0.03	[3]	$ 0.09	[3]	$ 0.16	[3]	$ 0.09	[3]	$ 2.10	$ 0.37	$ 0.33
Diluted (in dollars per share)	$ 1.42	[1],[3]	$ 0.06	[3]	$ 0.33	[3]	$ 0.24	[3]	$ 0.02	[3]	$ 0.09	[3]	$ 0.16	[3]	$ 0.09	[3]	$ 2.06	$ 0.37	$ 0.33
Average shares [Abstract]
Basic (in shares)	29,874		29,711		29,623		29,602		29,520		29,483		29,419		29,448		29,703	29,468	29,361
Diluted (in shares)	30,717		30,587		29,912		29,886		29,711		29,528		29,493		29,518		30,314	29,564	29,468
Deferred tax asset valuation allowance change in amount	36,287
Deferred tax assets, statutory rate change	$ 1,328

[1] Income from continuing operations includes the reversal of a valuation allowance on deferred tax assets of $36,287 and the impact on deferred taxes of a statutory rate change of $1,328.

[2] Discontinued operations includes charges for environmental remediation related to sites of divested businesses.

[3] 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 my not necessarily equal the earnings per share amount for the year.