Segment Reporting Operating Activity Within Reportable Segments (Detail) - USD ($) $ in Thousands	3 Months Ended								8 Months Ended	12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Operating income (loss)	$ 22,091	$ 27,275	$ 17,249	$ 12,920	$ 23,792	$ 26,477	$ 20,048	$ 23,329	$ (3,670)	$ 79,535	$ 93,646	$ 97,941
Total segments' profit										209,412	198,306	187,157
Total Retail
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax										105,552	103,968	100,982
Property expense										(30,078)	(28,524)	(27,934)
Operating income (loss)										75,474	75,444	73,048
Total Office
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax										112,362	105,694	103,254
Property expense										(33,860)	(33,120)	(31,839)
Operating income (loss)										78,502	72,574	71,415
Total Multifamily
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax										50,627	43,533	29,188
Property expense										(20,441)	(17,898)	(12,498)
Operating income (loss)										30,186	25,635	16,690
Total Mixed-Use
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax										62,326	61,788	61,664
Property expense										(37,076)	(37,135)	(35,660)
Operating income (loss)										$ 25,250	$ 24,653	$ 26,004