SELECTED QUARTERLY FINANCIAL DATA (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
Segment Reporting [Abstract]
Net revenues	$ 134,625	$ 130,570	$ 132,178	$ 129,492	$ 125,771	$ 125,892	$ 127,015	$ 126,603	$ 526,865	$ 505,281	$ 473,834
Cost of revenues	57,428	56,203	56,856	55,507	54,110	53,806	53,788	53,450	225,994	215,154	195,822
Gross profit	77,197	74,367	75,322	73,985	71,661	72,086	73,227	73,153	300,871	290,127
Operating income	3,078	8,582	11,506	11,571	10,253	8,690	11,395	11,088	34,737	41,426	35,956
Income (loss) from continuing operations	(1,280)	4,845	8,108	7,181	9,416	5,720	6,693	6,226	18,854	28,055	16,888
Loss on discontinued operations	(120)	(182)	(133)	(103)	(131)	(61)	(226)	(47)	(538)	(465)	4,546
Net income	$ (1,400)	$ 4,663	$ 7,975	$ 7,078	$ 9,285	$ 5,659	$ 6,467	$ 6,179	$ 18,316	$ 27,590	$ 21,434
Basic net income (loss) per share
Continuing operations	$ (0.03)	$ 0.10	$ 0.18	$ 0.16	$ 0.20	$ 0.12	$ 0.14	$ 0.13	$ 0.41	$ 0.59	$ 0.34
Discontinued operations	$ 0.00	$ 0.00	$ 0.00	$ 0.00	$ 0.00	$ 0.00	$ 0.00	$ 0.00	$ (0.01)	$ (0.01)	$ 0.09
Net income (loss) per share	$ (0.03)	$ 0.10	$ 0.17	$ 0.15	$ 0.20	$ 0.12	$ 0.13	$ 0.13	$ 0.40	$ 0.58	$ 0.43
Diluted net income (loss) per share
Continuing operations	$ (0.03)	$ 0.10	$ 0.17	$ 0.15	$ 0.20	$ 0.12	$ 0.14	$ 0.13	$ 0.40	$ 0.58	$ 0.34
Discontinued operations	$ 0.00	$ 0.00	$ 0.00	$ 0.00	$ 0.00	$ 0.00	$ 0.00	$ 0.00	$ (0.01)	$ (0.01)	$ 0.09
Net income (loss) per share	$ (0.03)	$ 0.10	$ 0.17	$ 0.15	$ 0.20	$ 0.12	$ 0.13	$ 0.13	$ 0.39	$ 0.57	$ 0.43