Significant Accounting Policies (Details 4) $ in Thousands	9 Months Ended
	Sep. 30, 2015 USD ($)
Changes in accumulated other comprehensive income (loss)
Beginning Balance	$ 5,951,734
Ending Balance	5,120,567
Accumulated Other Comprehensive Income (Loss)
Changes in accumulated other comprehensive income (loss)
Beginning Balance	(71,428)
Other comprehensive (loss) before reclassifications	(146,451)
Amounts reclassified from accumulated other comprehensive income (loss)	(72,090)
Net current-period other comprehensive income (loss)	(218,541)
Ending Balance	(289,969)
Currency translation adjustments
Changes in accumulated other comprehensive income (loss)
Beginning Balance	(129,554)
Other comprehensive (loss) before reclassifications	(144,826)
Net current-period other comprehensive income (loss)	(144,826)
Ending Balance	(274,380)
Accumulated derivative losses, net
Changes in accumulated other comprehensive income (loss)
Beginning Balance	(45,824)
Other comprehensive (loss) before reclassifications	12,455
Amounts reclassified from accumulated other comprehensive income (loss)	8,097
Net current-period other comprehensive income (loss)	20,552
Ending Balance	(25,272)
Net gain (loss) on marketable securities
Changes in accumulated other comprehensive income (loss)
Beginning Balance	103,950
Other comprehensive (loss) before reclassifications	(14,080)
Amounts reclassified from accumulated other comprehensive income (loss)	(80,187)
Net current-period other comprehensive income (loss)	(94,267)
Ending Balance	$ 9,683