Operating Activity Within Reportable Segments (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Segment Reporting Information [Line Items]
OPERATING INCOME	$ 19,880	$ 16,811
Total Segments' profit	41,094	35,390
Total Retail
Segment Reporting Information [Line Items]
Property revenue	22,154	21,691
Property expense	(4,971)	(5,726)
OPERATING INCOME	17,183	15,965
Total Office
Segment Reporting Information [Line Items]
Property revenue	22,422	17,887
Property expense	(6,436)	(5,518)
OPERATING INCOME	15,986	12,369
Total Multifamily
Segment Reporting Information [Line Items]
Property revenue	3,875	3,542
Property expense	(1,442)	(1,314)
OPERATING INCOME	2,433	2,228
Total Mixed-Use
Segment Reporting Information [Line Items]
Property revenue	13,729	12,329
Property expense	(8,237)	(7,501)
OPERATING INCOME	$ 5,492	$ 4,828