Consolidated Statements Of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
OPERATING ACTIVITIES
Net income	$ 8,764,000	$ 21,781,000	$ 28,691,000
Adjustments to reconcile net income to net cash provided by operating activities:
Impairment charges / (reversals)	6,347,000	(365,000)	3,101,000
Gain on extinguishment of debt obligations			(1,423,000)
Gain on sales	(59,000)		(14,376,000)
Straight-line rents	(38,000)	(506,000)	(761,000)
Provision for doubtful accounts	1,198,000	1,463,000	1,985,000
Depreciation and amortization	40,787,000	38,594,000	38,700,000
Amortization of intangible lease liabilities	(2,751,000)	(3,125,000)	(4,322,000)
Expense relating to share-based compensation, net	2,930,000	3,168,000	3,531,000
Amortization (including accelerated write-off) of deferred financing costs	1,778,000	1,611,000	2,158,000
Changes in operating assets and liabilities, net of effects of acquisitions and dispositions:
Rents and other receivables	(942,000)	(1,346,000)	(2,989,000)
Prepaid expenses and other	(1,418,000)	(1,929,000)	(2,460,000)
Accounts payable and accrued liabilities	929,000	(210,000)	(950,000)
Net cash provided by operating activities	57,525,000	59,136,000	50,885,000
INVESTING ACTIVITIES
Acquisitions of real estate	(31,923,000)	(42,991,000)	(38,861,000)
Expenditures for real estate improvements	(15,484,000)	(12,698,000)	(16,254,000)
Net proceeds from sales of real estate	96,170,000	5,891,000	102,124,000
Construction escrows and other	2,301,000	1,922,000	2,107,000
Net cash provided by / (used in) investing activities	51,064,000	(47,876,000)	49,116,000
FINANCING ACTIVITIES
Repayments under revolving credit facility	(197,000,000)	(186,400,000)	(231,500,000)
Advances under revolving credit facility	191,000,000	192,400,000	150,000,000
Advances under term loans	100,000,000	100,000,000	150,000,000
Mortgage borrowing	50,000,000
Mortgage repayments	(218,757,000)	(114,828,000)	(177,094,000)
Payments of debt financing costs	(1,355,000)	(2,879,000)	(1,312,000)
Noncontrolling interests:
Purchase of joint venture minority interests share		(11,216,000)
Distributions of consolidated joint venture minority interests			(960,000)
Distributions to limited partners	(71,000)	(78,000)	(86,000)
Redemptions of OP Units	(8,000)	(7,000)	(437,000)
Common stock sales less issuance expenses, net	(142,000)	41,741,000	41,163,000
Preferred stock dividends	(14,408,000)	(14,408,000)	(14,408,000)
Distributions to common shareholders	(17,049,000)	(17,001,000)	(15,841,000)
Net cash used in financing activities	(107,790,000)	(12,676,000)	(100,475,000)
Net increase (decrease) in cash and cash equivalents	799,000	(1,416,000)	(474,000)
Cash and cash equivalents at beginning of year	2,083,000	3,499,000	3,973,000
Cash and cash equivalents at end of year	$ 2,882,000	$ 2,083,000	$ 3,499,000