SELECTED QUARTERLY FINANCIAL AND SUPPLEMENTARY DATA - UNAUDITED (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended																12 Months Ended
	Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013		Mar. 31, 2013		Dec. 31, 2012		Sep. 30, 2012		Jun. 30, 2012		Mar. 31, 2012		Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Summary of selected quarterly financial and supplementary data [Abstract]
Gross Sales	$ 103,011		$ 77,992		$ 61,628		$ 74,581	[1]	$ 70,389	[2]	$ 59,841		$ 77,142		$ 70,559		$ 317,212	$ 277,931	$ 254,475
Net revenues	103,036		77,452		62,803		74,885	[1]	69,930	[2]	59,210		77,133		70,228		318,176	276,501	255,653
Gross profit	33,938		24,966		19,251		24,749	[1]	21,083	[2]	18,531		28,445		22,428		102,904	90,487	74,084
Income from continuing operations	9,440		6,274		3,136		11,425	[1]	44,242	[2]	2,021		9,928		7,038		30,275	63,229	13,735
Loss from discontinued operations	(541)	[3]	(2,700)	[3]	(862)	[3]	(257)	[1],[3]	(594)	[2],[3]	(332)	[3]	0	[3]	0	[3]	(4,360)	(926)	(2,767)
Net income	8,899		3,574		2,274		11,168	[1]	43,648	[2]	1,689		9,928		7,038		25,915	62,303	10,968
Earnings per share of common stock [Abstract]
Basic (in dollars per share)	$ 0.29	[4]	$ 0.12	[4]	$ 0.07	[4]	$ 0.37	[1],[4]	$ 1.46	[2],[4]	$ 0.06	[4]	$ 0.34	[4]	$ 0.24	[4]	$ 0.86	$ 2.10	$ 0.37
Diluted (in dollars per share)	$ 0.29	[4]	$ 0.12	[4]	$ 0.07	[4]	$ 0.36	[1],[4]	$ 1.42	[2],[4]	$ 0.06	[4]	$ 0.33	[4]	$ 0.24	[4]	$ 0.84	$ 2.06	$ 0.37
Average shares [Abstract]
Basic (in shares)	30,353		30,184		30,089		29,970	[1]	29,874	[2]	29,711		29,623		29,602		30,150	29,703	29,468
Diluted (in shares)	31,166		31,052		30,956		30,788	[1]	30,717	[2]	30,587		29,912		29,886		30,901	30,314	29,564
Deferred tax asset valuation allowance change in amount									36,287
Deferred tax assets, statutory rate change									1,328
Gain on the sale of an office building							4,680										4,680	0	0
Income tax expense on gain on sale of office building							1,470
Income tax benefit due to changes in tax laws							$ 1,155

[1] Income from continuing operations includes a gain on sale of an office building of $4,680 and a corresponding tax expense of $1,470 and a benefit of $1,155 due to changes in tax laws.

[2] 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.

[3] Discontinued operations include charges 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.