Significant Accounting Policies (Details 6) $ in Thousands	3 Months Ended
	Mar. 31, 2015 USD ($)
Significant Accounting Policies
Beginning balance	$ (61,041)
Other comprehensive income (loss) before reclassifications	(93,036)
Amounts reclassified from accumulated other comprehensive income (loss)	2,246
Net current-period other comprehensive income (loss)	(90,790)
Ending balance	(151,831)
Currency translation adjustments
Significant Accounting Policies
Beginning balance	(110,722)
Other comprehensive income (loss) before reclassifications	(106,514)
Net current-period other comprehensive income (loss)	(106,514)
Ending balance	(217,236)
Accumulated derivative losses, net
Significant Accounting Policies
Beginning balance	(39,161)
Other comprehensive income (loss) before reclassifications	8,618
Amounts reclassified from accumulated other comprehensive income (loss)	2,246
Net current-period other comprehensive income (loss)	10,864
Ending balance	(28,297)
Net unrealized gains (losses) on marketable securities
Significant Accounting Policies
Beginning balance	88,842
Other comprehensive income (loss) before reclassifications	4,860
Net current-period other comprehensive income (loss)	4,860
Ending balance	$ 93,702