Financial Instruments and Fair Value Measurements - Summary of Gains (Losses) From Change in Fair Value of Derivative Instruments Included in Other Comprehensive Income (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total derivative instruments	$ 15,586	$ (29,446)	$ 7,602	$ 37,541
Total derivative and nonderivative hedging instruments	107,002	(140,983)	(62,171)	260,944
Designated As Hedging Instrument [Member] | Derivative Net Investment Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total derivative instruments	21,512	(28,984)	29,420	34,194
Designated As Hedging Instrument [Member] | Interest Rate Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total derivative instruments	(2,672)	(2,341)	(13,790)	(759)
Designated As Hedging Instrument [Member] | Our Share of Derivatives from Unconsolidated Co-Investment Ventures [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total derivative instruments	(3,223)	1,879	(7,994)	4,106
Designated As Hedging Instrument [Member] | Cash Flow Hedge [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total derivative instruments	(31)	0	(34)	0
Non-Derivative Net Investment Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Nonderivative net investment hedges	$ 91,416	$ (111,537)	$ (69,773)	$ 223,403