Significant Accounting Policies (Details 6) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	$ (90,900)
Other comprehensive income (loss) before reclassifications	(14,917)
Amounts reclassified from accumulated other comprehensive income (loss)	3,490
Other comprehensive income (loss)	(11,427)
Ending balance	(102,327)
Currency translation adjustments
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	(26,220)
Other comprehensive income (loss) before reclassifications	(18,754)
Other comprehensive income (loss)	(18,754)
Ending balance	(44,974)
Accumulated derivative losses, net
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	(66,917)
Other comprehensive income (loss) before reclassifications	4,535
Amounts reclassified from accumulated other comprehensive income (loss)	3,490
Other comprehensive income (loss)	8,025
Ending balance	(58,892)
Net unrealized gains on marketable securities
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	2,237
Other comprehensive income (loss) before reclassifications	(698)
Other comprehensive income (loss)	(698)
Ending balance	$ 1,539