Comprehensive Income (Reclassifications out of Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Unrealized net losses on available-for-sale securities		$ (981)	$ (494)	$ (3,166)	$ 781
Unrealized net gains on cash flow hedges		448,275	441,936	1,347,824	1,338,503
Net income		(126,720)	$ (131,901)	(263,170)	$ (336,262)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net income		(996)		211
Unrealized Gain on Available-for-sale Securities [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Unrealized net losses on available-for-sale securities		120		(340)
Unrealized Gain on Derivative Instruments [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Unrealized net gains on cash flow hedges	[1]	$ (1,116)		$ 551

[1] Operating expenses amounts allocated to Research and development, Sales, marketing and services, and General and administrative are not individually significant.