Condensed Consolidated Statements Of Income (USD $) In Thousands, except Per Share data	3 Months Ended			9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010		Sep. 30, 2011	Sep. 30, 2010
Condensed Consolidated Statements Of Income [Abstract]
Revenues	$ 413,802	$ 346,140	[1]	$ 1,176,055	$ 1,045,213	[1]
Operating expenses
Direct cost of revenues	249,975	206,831	[1]	723,903	617,640	[1]
Selling, general and administrative expense	98,562	86,115	[1]	282,902	253,196	[1]
Special charges				15,212	29,356	[1]
Amortization of other intangible assets	5,843	6,286	[1]	16,795	18,229	[1]
Costs and expenses, total	354,380	299,232	[1]	1,038,812	918,421	[1]
Operating income	59,422	46,908	[1]	137,243	126,792	[1]
Other income (expense)
Interest income and other	486	2,527	[1]	5,409	4,740	[1]
Interest expense	(14,319)	(11,904)	[1]	(44,129)	(34,600)	[1]
Loss on early extinguishment of debt		(5,161)	[1]		(5,161)	[1]
Other income (expense), total	(13,833)	(14,538)	[1]	(38,720)	(35,021)	[1]
Income before income tax provision	45,589	32,370	[1]	98,523	91,771	[1]
Income tax provision	16,150	12,206	[1]	34,501	34,642	[1]
Net income	$ 29,439	$ 20,164	[1]	$ 64,022	$ 57,129	[1]
Earnings per common share-basic	$ 0.73	$ 0.44	[1]	$ 1.54	$ 1.25	[1]
Earnings per common share-diluted	$ 0.70	$ 0.43	[1]	$ 1.47	$ 1.19	[1]

[1] As Revised (Note 2)