Comprehensive Income (Reclassifications out of Accumulated Other Comprehensive Loss) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Other (expense) income, net	$ (766)	$ 722
Operating expenses	501,377	422,402
Net income	59,688	68,267
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Net income	(439)
Unrealized net gains on available-for-sale securities [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Other (expense) income, net	85
Unrealized net losses on cash flow hedges [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Operating expenses	$ (524)