Real Estate Activities - Summary of Operations for Disposed Assets (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
2018 [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Revenues		$ 88,838	$ 132,039	$ 109,544
Real estate depreciation and amortization		(15,849)	(31,870)	(26,410)
Property-related expenses		(531)	(404)	(45)
Other income (expense)	[1]	709,717	(14,168)	(23,937)
Income from real estate dispositions, net		$ 782,175	$ 85,597	59,152
2016 [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Revenues				8,350
Real estate depreciation and amortization				(2,870)
Property-related expenses				(113)
Other income (expense)	[2]			60,283
Income from real estate dispositions, net				$ 65,650

[1] Includes approximately $720 million of gains on sale for the twelve months ended December 31, 2018.

[2] Includes approximately $60 million of net gains on sale for the year ended December 31, 2016.