Quarterly Consolidated Financial Data (unaudited) (Details) (USD $) In Thousands, except Per 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
Quarterly Consolidated Financial Data (unaudited) [Abstract]
Revenues	$ 54,299	$ 62,152	$ 56,326	$ 45,709	$ 43,620	$ 41,434	$ 51,543	$ 50,599	$ 218,486	$ 187,196	$ 195,305
Gross Profit	28,563	33,125	30,222	23,765	22,943	22,254	27,859	27,297	115,675	100,353	103,900
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest	6,032	10,571	9,931	2,873	(1,019)	5,333	7,930	8,150	29,407	20,394	30,537
Net Income (Loss) Attributable to Parent	$ 28,996	$ 6,661	$ 6,346	$ 1,862	$ 6,230	$ 5,300	$ 6,957	$ 6,739	$ 43,865	$ 25,226	$ 27,015
Earnings Per Share, Basic	$ 0.90	$ 0.21	$ 0.20	$ 0.06	$ 0	$ 0	$ 0	$ 0	$ 1.36	$ 0.79	$ 0.86
Earnings Per Share, Diluted	$ 0.88	$ 0.20	$ 0.19	$ 0.06	$ 0	$ 0	$ 0	$ 0	$ 1.34	$ 0.78	$ 0.86
Weighted Average Number of Shares Outstanding, Basic	32,354	32,317	32,144	32,026	31,873	31,829	31,589	31,537	32,226	31,744	31,286
Weighted Average Number of Shares Outstanding, Diluted	33,045	32,862	32,727	32,713	32,458	32,309	32,038	32,071	32,853	32,256	31,492