Reportable Business Segments (Details 2) (USD $) In Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Reconciliation of segment operating income to consolidated income before income taxes
Segment operating income	$ 177,816	$ 179,817	$ 561,222	$ 481,728
Interest expense	(10,498)	(10,568)	(31,885)	(30,549)
Stock-based compensation expense	(7,630)	(6,965)	(21,011)	(18,580)
Change in contingent acquisition related obligations			17,813
Casualty loss related to flood	(12,831)		(12,831)
Total
Reconciliation of segment operating income to consolidated income before income taxes
Segment operating income	215,485	205,184	629,936	554,829
Unallocated amount to segment
Reconciliation of segment operating income to consolidated income before income taxes
Interest expense	(10,498)	(10,568)	(31,885)	(30,549)
Interest Income	2,871	1,537	7,000	3,456
Stock-based compensation expense	(7,630)	(6,965)	(21,011)	(18,580)
Change in contingent acquisition related obligations			17,813
Casualty loss related to flood	(12,831)		(12,831)
Other costs, net	$ (9,581)	$ (9,371)	$ (27,800)	$ (27,428)