Business Segments (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Revenue	$ 56,582	$ 57,052	$ 58,141	$ 59,750	$ 58,119	$ 56,910	$ 56,081	$ 56,109	$ 231,525	$ 227,219	$ 226,299
Expenses									(57,933)	(55,578)	(54,686)
Income from real estate									173,592	171,641	171,613
Interest expense, net and amortization of deferred debt costs									(41,834)	(44,768)	(47,145)
General and administrative									(20,793)	(18,459)	(18,176)
Depreciation and amortization of deferred leasing costs									(46,333)	(45,861)	(45,694)
Change in fair value of derivatives									(436)	(3)	70
Gain on sale of property										509
Net income (loss)									64,196	63,059	60,668
Capital investment									135,663	128,650	119,994
Total assets	1,618,340				1,527,489				1,618,340	1,527,489	1,422,452
Operating Segments | Shopping Centers
Segment Reporting Information [Line Items]
Revenue									167,888	164,344	165,232
Expenses									(36,119)	(34,643)	(34,054)
Income from real estate									131,769	129,701	131,178
Interest expense, net and amortization of deferred debt costs									0	0	0
General and administrative									0	0	0
Depreciation and amortization of deferred leasing costs									(29,112)	(29,251)	(29,977)
Change in fair value of derivatives									0	0	0
Gain on sale of property										509
Net income (loss)									102,657	100,959	101,201
Capital investment									33,968	13,485	90,896
Total assets	980,096				971,321				980,096	971,321	974,061
Operating Segments | Mixed-Use Properties
Segment Reporting Information [Line Items]
Revenue									63,637	62,875	61,067
Expenses									(21,814)	(20,935)	(20,632)
Income from real estate									41,823	41,940	40,435
Interest expense, net and amortization of deferred debt costs									0	0	0
General and administrative									0	0	0
Depreciation and amortization of deferred leasing costs									(17,221)	(16,610)	(15,717)
Change in fair value of derivatives									0	0	0
Gain on sale of property										0
Net income (loss)									24,602	25,330	24,718
Capital investment									101,695	115,165	29,098
Total assets	625,183				537,500				625,183	537,500	438,283
Corporate
Segment Reporting Information [Line Items]
Revenue									0	0	0
Expenses									0	0	0
Income from real estate									0	0	0
Interest expense, net and amortization of deferred debt costs									(41,834)	(44,768)	(47,145)
General and administrative									(20,793)	(18,459)	(18,176)
Depreciation and amortization of deferred leasing costs									0	0	0
Change in fair value of derivatives									(436)	(3)	70
Gain on sale of property										0
Net income (loss)									(63,063)	(63,230)	(65,251)
Capital investment									0	0	0
Total assets	$ 13,061				$ 18,668				$ 13,061	$ 18,668	$ 10,108