Financial Instruments and Fair Value Measurements - Summary of Changes in Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total derivative hedging instruments	$ (3,194)	$ 4,925
Total derivative and nonderivative hedging instruments – gains (losses)	(113,071)	(39,601)
Cumulative translation adjustment	111,554	81,899
Total change in other comprehensive income (loss)	(1,517)	42,298
Designated As Hedging Instrument [Member] | Derivative Net Investment Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total derivative hedging instruments	3,093	2,294
Designated As Hedging Instrument [Member] | Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total derivative hedging instruments	(9,285)	429
Designated As Hedging Instrument [Member] | Our Share of Derivatives from Unconsolidated Co-Investment Ventures [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total derivative hedging instruments	2,998	2,202
Non-Derivative Net Investment Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Nonderivative net investment hedges	$ (109,877)	$ (44,526)