Segment Information (Identifiable Assets By Segment) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Identifiable assets	$ 4,796,402	$ 4,099,541
Long-lived assets	303,294	277,429
UNITED STATES
Long-lived assets	231,812	223,076
UNITED KINGDOM
Long-lived assets	30,633	28,344
Other Countries [Member]
Long-lived assets	40,849	26,009
Enterprise Divisions [Member]
Identifiable assets	4,246,292	3,619,989
Online Services division revenues
Identifiable assets	$ 550,110	$ 479,552