Equity (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning Balance	$ (35,366)	$ (32,601)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(15,131)	14,257
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	236	132
Total other comprehensive (loss) income	(14,895)	14,389
Accumulated Other Comprehensive Income (Loss), Net of Tax, Ending Balance	(50,261)	(18,212)
Interest Expense AOCI reclass
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	941	888
Other (Income) And Expense
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(705)	(756)
Gains and Losses on Derivative Instruments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning Balance	(25,888)	(8,765)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	9,963	(5,783)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	236	132
Total other comprehensive (loss) income	10,199	(5,651)
Accumulated Other Comprehensive Income (Loss), Net of Tax, Ending Balance	(15,689)	(14,416)
Gains and Losses on Derivative Instruments | Interest Expense AOCI reclass
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	941	888
Gains and Losses on Derivative Instruments | Other (Income) And Expense
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(705)	(756)
Unrealized Gains and Losses on Marketable Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning Balance	(470)	(1,506)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	24	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0	0
Total other comprehensive (loss) income	24	0
Accumulated Other Comprehensive Income (Loss), Net of Tax, Ending Balance	(446)	(1,506)
Unrealized Gains and Losses on Marketable Securities | Interest Expense AOCI reclass
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0	0
Unrealized Gains and Losses on Marketable Securities | Other (Income) And Expense
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0	0
Accumulated Translation Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning Balance	(9,008)	(22,330)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(25,118)	20,040
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0	0
Total other comprehensive (loss) income	(25,118)	20,040
Accumulated Other Comprehensive Income (Loss), Net of Tax, Ending Balance	(34,126)	(2,290)
Accumulated Translation Adjustment | Interest Expense AOCI reclass
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0	0
Accumulated Translation Adjustment | Other (Income) And Expense
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	$ 0	$ 0