Real Estate Activities (Narrative) (Detail) - USD ($) $ in Thousands	3 Months Ended										12 Months Ended
	Dec. 31, 2018	[1]	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017		Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Real Estate Properties [Line Items]
Impairment Of Assets											$ 137,487	$ 55,793	$ 62,603
Gain or loss on sale of real estate				$ 700		$ 8,100					8,100	1,270	380
Income recognized from grant	$ (78,782)		$ (745)	$ (28,201)	$ (2,601)	$ 8,883	[1]	$ 11,793	$ (46,856)	$ 227	(110,329)	(25,953)	(9,663)
Repayment of mortgage loans											$ 0	$ 150,000	$ 280,327

[1] Fourth Quarter revenue includes a significant portion of annual percentage rent as most percentage rent minimum sales levels are met in the fourth quarter.