Condensed Consolidated Statements Of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Condensed Consolidated Statements Of Operations [Abstract]
Net revenues	$ 500,878	$ 431,567
Costs and expenses:
Cost of goods and services	163,529	124,209
Operating expenses	114,982	101,907
Selling, general and administrative expenses	93,396	82,879
Bad debt expense	10,018	8,631
Depreciation and amortization expense	32,552	29,317
Total costs and expenses	414,477	346,943
Operating income	86,401	84,624
Other income (expense):
Interest income	114	203
Interest expense	(10,324)	(9,258)
Total other income (expense)	(10,210)	(9,055)
Income before income taxes	76,191	75,569
Income tax expense	29,791	29,192
Net income	$ 46,400	$ 46,377
Basic earnings per common share	$ 0.55	$ 0.50
Diluted earnings per common share	$ 0.54	$ 0.49
Dividends declared per common share	$ 0.20	$ 0.20
Weighted average number of common shares outstanding	83,763	92,978
Weighted average number of common shares and common share equivalents outstanding	86,172	95,466