QUARTERLY FINANCIAL DATA: (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended																12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	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, 2014	Dec. 31, 2013	Dec. 31, 2012
Net revenue	$ 109,730	$ 112,171	$ 108,414	$ 111,072	$ 111,595	$ 118,391	[1]	$ 119,602	[1]	$ 99,112	[1]	$ 105,885	$ 109,894	$ 105,830	[2]	$ 102,964	$ 441,387	$ 448,700	$ 424,573
Operating income	19,424	19,560	22,350	15,831	17,388	21,795	[1]	18,330	[1]	15,455	[1]	14,601	21,498	21,385	[2]	13,725	77,165	72,968	71,209
Net (loss) income from continuing operations	(8,272)	(8,758)	(5,408)	(20,302)	(13,631)	(8,904)	[1]	(8,555)	[1]	(13,305)	[1]	(15,013)	(10,215)	46,452	[2]	(75,156)	(42,740)	(44,395)	(53,932)
Income (loss) from discontinued operations					(8)	0	[1]	3	[1]	890	[1]	(128)	(40)	13	[2]	(29)	0	885	(184)
Consolidated net loss attributable to common stockholders	$ (13,451)	$ (13,220)	$ (10,816)	$ (25,183)	$ (16,440)	$ (13,221)	[1]	$ (14,214)	[1]	$ (18,106)	[1]	$ (17,227)	$ (13,064)	$ 42,668	[2]	$ (79,242)	$ (62,670)	$ (61,981)	$ (66,865)
BASIC NET (LOSS) INCOME ATTRIBUTABLE TO COMMON STOCKHOLDERS
Net (loss) income from continuing operations per share (in dollars per share)	$ (0.28)	$ (0.28)	$ (0.23)	$ (0.53)	$ (0.35)	$ (0.28)	[1]	$ (0.29)	[1]	$ (0.38)	[1]	$ (0.34)	$ (0.26)	$ 0.85	[2]	$ (1.58)	$ (1.32)	$ (1.30)	$ (1.33)
Net (loss) income from discontinued operations per share (in dollars per share)					$ 0.00	$ 0	[1]	$ 0.00	[1]	$ 0.02	[1]	$ 0.00	$ 0.00	$ 0.00	[2]	$ 0.00	$ 0.00	$ 0.02	$ 0.00
Consolidated net (loss) income per share attributable to common stockholders (in dollars per share)	$ (0.28)	$ (0.28)	$ (0.23)	$ (0.53)	$ (0.35)	$ (0.28)	[1]	$ (0.29)	[1]	$ (0.36)	[1]	$ (0.34)	$ (0.26)	$ 0.85	[2]	$ (1.58)	$ (1.32)	$ (1.28)	$ (1.34)	[3]
DILUTED NET (LOSS) INCOME ATTRIBUTABLE TO COMMON STOCKHOLDERS
Net (loss) income from continuing operations per share (in dollars per share)	$ (0.28)	$ (0.28)	$ (0.23)	$ (0.53)	$ (0.35)	$ (0.28)	[1]	$ (0.29)	[1]	$ (0.38)	[1]	$ (0.34)	$ (0.26)	$ 0.85	[2]	$ (1.58)
Net (loss) income from discontinued operations per share (in dollars per share)					$ 0.00	$ 0	[1]	$ 0.00	[1]	$ 0.02	[1]	$ 0.00	$ 0.00	$ 0.00	[2]	$ 0.00
Consolidated net (loss) income per share attributable to common stockholders (in dollars per share)	$ (0.28)	$ (0.28)	$ (0.23)	$ (0.53)	$ (0.35)	$ (0.28)	[1]	$ (0.29)	[1]	$ (0.36)	[1]	$ (0.34)	$ (0.26)	$ 0.85	[2]	$ (1.58)
WEIGHTED AVERAGE SHARES OUTSTANDING
Weighted average shares outstanding - basic and diluted (in shares)	47,608,038	47,601,371	47,465,653	47,441,175	47,441,175	47,443,031	[1]	48,737,941	[1]	49,861,964	[1]						47,525,726	48,370,195	50,015,252
Weighted average shares outstanding - basic (in shares)												50,042,751	50,019,048	50,006,008	[2]	49,994,974
Weighted average shares outstanding - diluted (in shares)												50,042,751	50,019,048	50,124,418	[2]	49,994,974

[1] The net loss from continuing operations for the quarters ended March 31, 2013, June 30, 2013 and September 30, 2013 includes approximately $1.4 million, $9.8 million and $3.7 million, respectively of impairment charges.

[2] The net income from continuing operations for the quarter ended June 30, 2012, includes $313,000 of impairment charges.

[3] Per share amounts do not add due to rounding.