Segment Reporting Operating Activity Within Reportable Segments (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Operating income (loss)	$ 25,110	$ 25,484	$ 23,704	$ 23,643	$ 23,893	$ 23,510	$ 23,504	$ 23,244	$ 97,941	$ 94,151	$ 83,669
Total segments' profit									187,157	177,617	168,769
Total Retail
Segment Reporting Information [Line Items]
Property revenue									100,982	98,795	96,140
Property expense									(27,934)	(25,672)	(25,451)
Operating income (loss)									73,048	73,123	70,689
Total Office
Segment Reporting Information [Line Items]
Property revenue									103,254	97,651	92,474
Property expense									(31,839)	(28,843)	(27,003)
Operating income (loss)									71,415	68,808	65,471
Total Multifamily
Segment Reporting Information [Line Items]
Property revenue									29,188	19,455	16,976
Property expense									(12,498)	(8,334)	(6,099)
Operating income (loss)									16,690	11,121	10,877
Total Mixed-Use
Segment Reporting Information [Line Items]
Property revenue									61,664	59,722	54,410
Property expense									(35,660)	(35,157)	(32,678)
Operating income (loss)									$ 26,004	$ 24,565	$ 21,732