Schedule III - Changes in Total Real Estate Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017		Dec. 31, 2016	Dec. 31, 2015
SEC Schedule III, Real Estate and Accumulated Depreciation Disclosure [Abstract]
Balance at beginning of period	$ 3,968,042		$ 2,991,590	$ 2,040,727
Acquisitions	1,256,245		745,948	975,239
Transfers from construction in progress	36,828		163,080	23,163
Additions	30,646		33,279	7,376
Dispositions	(53,372)		(138,886)	(24,701)
Other	155,964		173,031	(30,214)
Balance at end of period	$ 5,438,148	[1]	$ 3,968,042	$ 2,991,590

[1] Includes real estate cost included in real estate held for sale of $131.3 million at December 31, 2017. Excludes intangible lease assets that are included in real estate held for sale of $15.5 million for 2017.