Consolidated Statements of Cash Flows - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities:
Net income		$ 60,668	$ 56,720	$ 52,931
Adjustments to reconcile net income to net cash provided by operating activities:
Change in fair value of derivatives		(70)	6	10
Gains on sales of properties		0	(1,013)	(11)
Depreciation and amortization of deferred leasing costs		45,694	44,417	43,270
Amortization of deferred debt costs		1,392	1,343	1,433
Non cash compensation costs of stock grants and options		1,672	1,603	1,434
Provision for credit losses		906	1,494	915
Increase in accounts receivable and accrued income		(1,643)	(3,525)	(5,216)
Additions to deferred leasing costs		(4,615)	(4,633)	(5,563)
Increase in prepaid expenses		(294)	(399)	(570)
(Increase) decrease in other assets		1,374	(6,368)	1,544
Increase (decrease) in accounts payable, accrued expenses and other liabilities		1,125	921	(937)
Decrease in deferred income		(2,759)	(1,476)	(344)
Net cash provided by operating activities		103,450	89,090	88,896
Cash flows from investing activities:
Acquisitions of real estate investments		(79,499)	(48,250)	(4,894)
Additions to real estate investments		(17,653)	(15,564)	(18,855)
Additions to development and redevelopment projects		(22,842)	(27,231)	(45,870)
Proceeds from sale of properties	[1]	6,688	4,771	32
Net cash used in investing activities		(113,306)	(86,274)	(69,587)
Cash flows from financing activities:
Proceeds from mortgage notes payable		100,000	11,250	46,000
Repayments on mortgage notes payable		(55,679)	(24,653)	(52,963)
Proceeds from construction loans payable		1,437	24,937	39,817
Proceeds from revolving credit facility		63,000	78,500	20,000
Repayments on revolving credit facility		(51,000)	(57,500)	(35,000)
Additions to deferred debt costs		(2,583)	(125)	(296)
Proceeds from the issuance of:
Common stock		22,751	21,564	15,583
Partnership units		6,735	6,910	5,673
Distributions to:
Series C preferred stockholders		(12,375)	(12,375)	(12,375)
Common stockholders		(44,576)	(39,472)	(35,645)
Noncontrolling interests		(15,268)	(13,533)	(12,228)
Net cash provided by (used in) financing activities		12,442	(4,497)	(21,434)
Net increase (decrease) in cash and cash equivalents		2,586	(1,681)	(2,125)
Cash and cash equivalents, beginning of year		8,322	10,003	12,128
Cash and cash equivalents, end of year		10,908	8,322	10,003
Supplemental disclosure of cash flow information:
Cash paid for interest		45,713	44,066	43,799
Increase (decrease) in accrued real estate investments and development costs		2,097	$ (7,098)	$ 5,201
Great Eastern Shopping Center
Property, Plant and Equipment [Line Items]
Seller financing		$ 1,275

[1] Proceeds from sales of property excludes $1,275 of seller financing in connection with the sale of the Company's Great Eastern property.