Organization and Summary of Significant Accounting Policies (Changes in Carrying Amount of Goodwill) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2015	Dec. 31, 2016	Sep. 30, 2015	Dec. 31, 2014
Goodwill [Line Items]
Goodwill divested			$ 0
Goodwill [Roll Forward]
Basis, Balance, beginning of period	$ 6,322	$ 6,735
Basis, Changes in Goodwill	0	(137)
Basis, Balance, end of period	6,322	6,322
Accumulated Amortization, Balance, beginning of period	1,073	1,073
Accumulated Amortization, Balance, end of period	1,073	1,073
Goodwill	$ 5,249	5,249	$ 5,249		$ 5,662
Goodwill, Impairment Loss		(276)
Palmer Park Mall [Member]
Goodwill [Roll Forward]
Goodwill, Impairment Loss		$ (300)
Springfield Park [Member]
Goodwill [Line Items]
Goodwill divested				$ 100