Consolidated Statements of Comprehensive Income (Loss) (USD $) In Thousands, except Per 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, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenues	$ 425,158	$ 451,178	$ 454,324	$ 425,552	$ 415,998	$ 414,643	$ 414,613	$ 407,178	$ 1,756,212	$ 1,652,432	$ 1,576,871
Operating expenses
Direct cost of revenues	281,689	293,244	295,549	274,275	268,901	255,152	259,528	258,480	1,144,757	1,042,061	980,532
Selling, general and administrative expenses	115,965	102,461	107,032	108,387	107,196	94,513	96,325	96,647	433,845	394,681	378,016
Special charges	1,628	5,347	9,364		27,568	10,419		427	16,339	38,414	29,557
Acquisition-related contingent consideration	(85)	257	(5)	(1,843)	(4,778)	630	(7,452)	731	(1,676)	(10,869)	(3,064)
Amortization of other intangible assets	4,055	3,398	3,452	4,616	5,661	5,776	5,953	5,564	15,521	22,954	22,407
Goodwill impairment charge						83,752				83,752	110,387
Costs and Expenses, Total	403,252	404,707	415,392	385,435	404,548	450,242	354,354	361,849	1,608,786	1,570,993	1,517,835
Operating income	21,906	46,471	38,932	40,117	11,450	(35,599)	60,259	45,329	147,426	81,439	59,036
Other income (expense)
Interest income and other									4,670	1,748	5,659
Interest expense	(12,488)	(12,634)	(12,908)	(12,655)	(12,776)	(12,814)	(13,071)	(12,715)	(50,685)	(51,376)	(56,731)
Loss on early extinguishment of debt											(4,850)
Other (expense) income									(46,015)	(49,628)	(55,922)
Income (loss) before income tax provision	10,623	34,851	27,472	28,465	(1,280)	(47,261)	46,801	33,551	101,411	31,811	3,114
Income tax provision	9,702	12,329	10,225	10,348	5,859	3,360	23,315	9,871	42,604	42,405	40,100
Net income (loss)	921	22,522	17,247	18,117	(7,139)	(50,621)	23,486	23,680	58,807	(10,594)	(36,986)
Earnings (loss) per common share - basic	$ 0.02	$ 0.57	$ 0.43	$ 0.46	$ (0.18)	$ (1.29)	$ 0.60	$ 0.60	$ 1.48	$ (0.27)	$ (0.92)
Earnings (loss) per common share - diluted	$ 0.02	$ 0.55	$ 0.42	$ 0.45	$ (0.18)	$ (1.29)	$ 0.58	$ 0.58	$ 1.44	$ (0.27)	$ (0.92)
Other comprehensive income (loss) net of tax:
Foreign currency translation adjustments, net of tax expense (benefit) of $0, $0 and $654 for the years ended December 31, 2014, 2013 and 2012, respectively									(29,179)	(9,720)	15,023
Other comprehensive income (loss), net of tax									(29,179)	(9,720)	15,023
Comprehensive income (loss)									$ 29,628	$ (20,314)	$ (21,963)