SELECTED QUARTERLY FINANCIAL DATA (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
SEGMENT REPORTING [Abstract]
Net revenues	$ 125,771	$ 125,892	$ 127,015	$ 126,603	$ 118,735	$ 119,184	$ 118,990	$ 116,925	$ 505,281	$ 473,834	$ 441,753
Cost of Revenue	54,110	53,806	53,788	53,450	49,227	49,938	49,315	47,342	215,154	195,822	178,699
Gross profit	71,661	72,086	73,227	73,153	69,508	69,246	69,675	69,583	290,127	278,012
Operating income	10,253	8,690	11,395	11,088	9,978	9,911	9,028	7,039	41,426	35,956	20,981
Income from continuing operations	9,416	5,720	6,693	6,226	3,281	5,822	4,853	2,932	28,055	16,888	8,966
Income (loss) on discontinued operations	(131)	(61)	(226)	(47)	(2,194)	6,735	36	(31)	(465)	4,546	(4,135)
Net income	$ 9,285	$ 5,659	$ 6,467	$ 6,179	$ 1,087	$ 12,557	$ 4,889	$ 2,901	$ 27,590	$ 21,434	$ 4,831
Basic net income (loss) per share
Continuing operations	$ 0.2	$ 0.12	$ 0.14	$ 0.13	$ 0.07	$ 0.12	$ 0.1	$ 0.06	$ 0.59	$ 0.34	$ 0.15
Discontinued operations	$ 0.0	$ 0.0	$ 0.0	$ 0.0	$ (0.05)	$ 0.14	$ 0.0	$ 0.0	$ (0.01)	$ 0.09	$ (0.07)
Net income per share	$ 0.2	$ 0.12	$ 0.13	$ 0.13	$ 0.02	$ 0.26	$ 0.1	$ 0.06	$ 0.58	$ 0.43	$ 0.08
Diluted net income (loss) per share
Continuing operations	$ 0.2	$ 0.12	$ 0.14	$ 0.13	$ 0.07	$ 0.12	$ 0.1	$ 0.06	$ 0.58	$ 0.34	$ 0.15
Discontinued operations	$ 0.0	$ 0.0	$ 0.0	$ 0.0	$ (0.04)	$ 0.14	$ 0.0	$ 0.0	$ (0.01)	$ 0.09	$ (0.07)
Net income per share	$ 0.2	$ 0.12	$ 0.13	$ 0.13	$ 0.02	$ 0.25	$ 0.1	$ 0.06	$ 0.57	$ 0.43	$ 0.08