Segment Information (Net Revenues And Profit By Segment) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012 segment		Mar. 31, 2011
Number of reportable segments	2
Net revenues	$ 589,495		$ 490,888
Amortization of intangible assets	(27,002)	[1]	(16,208)	[1]
Restructuring	0	[1]	(24)	[1]
Net interest and other income	3,800	[1]	7,572	[1]
Stock-based compensation	(30,557)	[1]	(17,884)	[1]
Income before income taxes	84,550		88,455
Enterprise Divisions [Member]
Net revenues	468,762		391,116
Segment profit	117,173		100,449
Online Services Division [Member]
Net revenues	120,733		99,772
Segment profit	$ 21,136		$ 14,550

[1] Represents expenses presented to management on a consolidated basis only and not allocated to the operating segments.