CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE (LOSS) INCOME - USD ($) $ in Thousands	3 Months Ended								6 Months Ended		9 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	Jun. 30, 2014	Jun. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE (LOSS) INCOME
Net revenue	$ 278,910	$ 261,699	$ 255,574	$ 215,917	$ 255,048	$ 253,217	$ 253,667	$ 213,837	$ 471,491	$ 467,504	$ 733,190	$ 720,721	$ 1,012,100	$ 975,769	$ 923,521
Material costs	86,365	86,238	81,109	70,572	77,831	78,933	77,273	67,966	151,681	145,239	237,919	224,172	324,284	302,003	285,873
Personnel costs	93,516	89,104	88,738	82,228	83,742	82,071	82,836	77,131	170,966	159,967	260,070	242,038	353,586	325,780	299,004
Other operating costs	35,636	34,621	34,291	32,337	27,398	28,526	28,620	31,223	66,628	59,843	101,249	88,369	136,885	115,767	110,881
General and administrative expenses	22,383	21,794	22,545	19,616	21,841	19,137	21,204	16,476	42,161	37,680	63,955	56,817	86,338	78,658	81,182
Professional accounting and legal fees	19,768	20,973	2,600	1,457	1,205	1,715	1,501	1,400	4,057	2,901	25,030	4,616	44,798	5,821	4,907
Depreciation and amortization	9,978	9,818	9,826	9,307	8,487	8,526	8,805	8,367	19,133	17,172	28,951	25,698	38,929	34,185	32,589
Income from operations	11,264	(849)	16,465	400	34,544	34,309	33,428	11,274	16,865	44,702	16,016	79,011	27,280	113,555	109,085
Interest expense, net	7,191	7,255	7,063	6,768	6,372	6,942	8,616	8,646	13,831	17,262	21,086	24,204	28,277	30,576	34,620
Extinguishment of debt							6,645			6,645		6,645		6,645
(Loss) income from continuing operations before income taxes	4,073	(8,104)	9,402	(6,368)	28,172	27,367	18,167	2,628	3,034	20,795	(5,070)	48,162	(997)	76,334	74,465
Provision for income taxes	1,267	(10,054)	10,832	(22)	13,077	9,815	6,688	875	10,810	7,563	756	17,378	2,023	30,455	26,206
(Loss) income from continuing operations	2,806	1,950	(1,430)	(6,346)	15,095	17,552	11,479	1,753	(7,776)	13,232	(5,826)	30,784	(3,020)	45,879	48,259
Loss from discontinued operations, net of income taxes	(6,235)	(10,751)	4,661	(3,621)	(3,063)	(2,034)	(282)	11	1,040	(271)	(9,711)	(2,305)	(15,946)	(5,368)	(235)
Net (loss) income	(3,429)	(8,801)	3,231	(9,967)	12,032	15,518	11,197	1,764	(6,736)	12,961	(15,537)	28,479	(18,966)	40,511	48,024
Other comprehensive (loss) income:
Unrealized (loss) gain on SERP, net of income tax (benefit) provision of $(525), $531 and $(439) for 2014, 2013 and 2012, respectively	(868)				899								(868)	899	(734)
Total other comprehensive (loss) income	(868)				899								(868)	899	(734)
Comprehensive (loss) income	$ (4,297)	$ (8,801)	$ 3,231	$ (9,967)	$ 12,931	$ 15,518	$ 11,197	$ 1,764	$ (6,736)	$ 12,961	$ (15,537)	$ 28,479	$ (19,834)	$ 41,410	$ 47,290
Basic Per Common Share Data
(Loss) income from continuing operations	$ 0.08	$ 0.05	$ (0.04)	$ (0.18)	$ 0.43	$ 0.50	$ 0.33	$ 0.05	$ (0.22)	$ 0.38	$ (0.17)	$ 0.89	$ (0.09)	$ 1.32	$ 1.41
Loss from discontinued operations, net of income taxes	(0.18)	(0.30)	0.13	(0.10)	(0.09)	(0.06)	(0.01)		0.03	(0.01)	(0.27)	(0.07)	(0.45)	(0.16)	(0.01)
Basic (loss) income per share (in dollars per share)	$ (0.10)	$ (0.25)	$ 0.09	$ (0.28)	$ 0.34	$ 0.44	$ 0.32	$ 0.05	$ (0.19)	$ 0.37	$ (0.44)	$ 0.82	$ (0.54)	$ 1.16	$ 1.40
Shares used to compute basic per common share amounts (in shares)	35,397,195	35,388,862	35,377,939	35,056,902	34,945,120	34,927,373	34,872,430	34,570,836	35,209,849	34,710,269	35,275,046	34,782,207	35,309,478	34,825,867	34,273,621
Diluted Per Common Share Data
(Loss) income from continuing operations	$ 0.08	$ 0.05	$ (0.04)	$ (0.18)	$ 0.43	$ 0.50	$ 0.33	$ 0.05	$ (0.22)	$ 0.38	$ (0.17)	$ 0.88	$ (0.09)	$ 1.30	$ 1.39
Loss from discontinued operations, net of income taxes	(0.18)	(0.30)	0.13	(0.10)	(0.09)	(0.06)	(0.01)		0.03	(0.01)	(0.27)	(0.07)	(0.45)	(0.15)	(0.01)
Diluted (loss) income per share (in dollars per share)	$ (0.10)	$ (0.25)	$ 0.09	$ (0.28)	$ 0.34	$ 0.44	$ 0.32	$ 0.05	$ (0.19)	$ 0.37	$ (0.44)	$ 0.81	$ (0.54)	$ 1.15	$ 1.38
Shares used to compute diluted per common share amounts (in shares)	35,615,092	35,571,188	35,377,939	35,056,902	35,364,729	35,298,046	35,211,878	35,062,115	35,209,849	35,124,223	35,275,046	35,180,990	35,309,478	35,208,754	34,737,420