Reportable Business Segments (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Reconciliation of segment operating income to consolidated income before income taxes
Segment operating income	$ 255,810	$ 224,013	$ 487,945	$ 430,970
Interest expense	(20,081)	(15,621)	(39,152)	(31,078)
Stock-based compensation expense	(9,973)	(8,890)	(19,249)	(17,175)
Acquisition-related expenses			(2,020)
Income before income taxes	240,022	211,425	457,151	405,710
Segment operating income
Reconciliation of segment operating income to consolidated income before income taxes
Segment operating income	275,983	242,525	529,297	467,426
Unallocated amount to segment
Reconciliation of segment operating income to consolidated income before income taxes
Interest expense	(20,081)	(15,621)	(39,152)	(31,078)
Interest Income	4,725	3,391	9,170	6,486
Stock-based compensation expense	(9,973)	(8,890)	(19,249)	(17,175)
Acquisition-related expenses			(2,020)
Other costs, net	(10,632)	(9,980)	(20,895)	(19,949)
Income before income taxes	$ 240,022	$ 211,425	$ 457,151	$ 405,710