Segment Information (Reconciliation of Total Segment Income from Operations to Consolidated Income before Income Taxes) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Segment Reporting [Abstract]
Income from operations	$ 295,374	$ 266,788	$ 524,654	$ 514,843
Interest expense	(8,958)	(9,539)	(18,549)	(18,696)
Other income, net	22,058	4,601	31,154	7,110
Income before income taxes	$ 308,474	$ 261,850	$ 537,259	$ 503,257