Equity (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning Balance	$ (38,789)	$ (50,735)	$ (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	20,909	5,061	15,346	(13,399)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	1,370	1,664	3,529	1,854
Net current-period Other comprehensive income (loss)	22,279	6,725	18,875	(11,545)
Net current-period Other comprehensive (income) loss attributable to noncontrolling interest	(550)	(331)	(569)	(195)
Accumulated Other Comprehensive Income (Loss), Net of Tax, Ending Balance	(17,060)	(44,341)	(17,060)	(44,341)
Interest expense
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	1,911	1,411	5,382	3,185
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	(541)	253	(1,853)	(1,331)
Unrealized gains and losses on derivative instruments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning Balance	(12,730)	(11,831)	(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	(11,592)	(8,113)	(339)	(11,219)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	1,370	910	3,529	1,100
Net current-period Other comprehensive income (loss)	(10,222)	(7,203)	3,190	(10,119)
Net current-period Other comprehensive (income) loss attributable to noncontrolling interest	(142)	(109)	(396)	(259)
Accumulated Other Comprehensive Income (Loss), Net of Tax, Ending Balance	(23,094)	(19,143)	(23,094)	(19,143)
Unrealized gains and losses on derivative instruments | Interest expense
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	1,911	1,411	5,382	3,185
Unrealized 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	(541)	(501)	(1,853)	(2,085)
Unrealized gains and losses on marketable securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning Balance	(423)	(523)	(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	(731)	71	252
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0	754	0	754
Net current-period Other comprehensive income (loss)	24	23	71	1,006
Net current-period Other comprehensive (income) loss attributable to noncontrolling interest	0	0	0	0
Accumulated Other Comprehensive Income (Loss), Net of Tax, Ending Balance	(399)	(500)	(399)	(500)
Unrealized gains and losses on marketable securities | Interest 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	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	754	0	754
Accumulated translation adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning Balance	(25,636)	(38,381)	(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	32,477	13,905	15,614	(2,432)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0	0	0	0
Net current-period Other comprehensive income (loss)	32,477	13,905	15,614	(2,432)
Net current-period Other comprehensive (income) loss attributable to noncontrolling interest	(408)	(222)	(173)	64
Accumulated Other Comprehensive Income (Loss), Net of Tax, Ending Balance	6,433	(24,698)	6,433	(24,698)
Accumulated translation adjustment | Interest 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	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	$ 0	$ 0