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		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total derivative instruments	$ 2,468	$ 16,242	$ 2,343	$ 23,844
Total derivative and nonderivative hedging instruments	(137,417)	(2,777)	(411,734)	(64,948)
Designated As Hedging Instrument [Member] | Derivative Net Investment Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total derivative instruments	(3,623)	11,546	(13,114)	40,966
Designated As Hedging Instrument [Member] | Interest Rate and Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total derivative instruments	5,553	3,110	10,382	(10,714)
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	538	1,586	5,075	(6,408)
Non-Derivative Net Investment Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Nonderivative net investment hedges	$ (139,885)	$ (19,019)	$ (414,077)	$ (88,792)