Retail Properties of America (RPAI) 10-Q 2 Aug 17 2017 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2017	Jul. 28, 2017
Entity Information [Line Items]
Entity Registrant Name	RETAIL PROPERTIES OF AMERICA, INC.
Entity Central Index Key	1,222,840
Document Type	10-Q
Document Period End Date	Jun. 30, 2017
Amendment Flag	false
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q2
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		230,942,762

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Investment properties:
Land	$ 1,141,172	$ 1,191,403
Building and other improvements	4,023,200	4,284,664
Developments in progress	28,254	23,439
Gross investment properties	5,192,626	5,499,506
Less accumulated depreciation	(1,363,604)	(1,443,333)
Net investment properties	3,829,022	4,056,173
Cash and cash equivalents	28,003	53,119
Accounts and notes receivable (net of allowances of $6,938 and $6,886, respectively)	71,588	78,941
Acquired lease intangible assets, net	131,092	142,015
Assets associated with investment properties held for sale	44,087	30,827
Other assets, net	160,531	91,898
Total assets	4,264,323	4,452,973
Liabilities:
Mortgages payable, net	355,239	769,184
Unsecured notes payable, net	695,441	695,143
Unsecured term loans, net	646,554	447,598
Unsecured revolving line of credit	182,000	86,000
Accounts payable and accrued expenses	65,093	83,085
Distributions payable	38,318	39,222
Acquired lease intangible liabilities, net	102,720	105,290
Liabilities associated with investment properties held for sale	1,142	864
Other liabilities	75,339	74,501
Total liabilities	2,161,846	2,300,887
Commitments and contingencies (Note 14)
Equity:
Additional paid-in capital	4,853,680	4,927,155
Accumulated distributions in excess of earnings	(2,752,648)	(2,776,033)
Accumulated other comprehensive income	1,209	722
Total equity	2,102,477	2,152,086
Total liabilities and equity	4,264,323	4,452,973
7.00% Series A cumulative redeemable preferred stock
Equity:
Preferred stock	5	5
Class A common stock
Equity:
Class A common stock	$ 231	$ 237

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (parenthetical) - USD ($) shares in Thousands, $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Accounts and notes receivable, allowances (in dollars)	$ 6,938	$ 6,886
7.00% Series A cumulative redeemable preferred stock
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized	10,000	10,000
Preferred stock, dividend rate	7.00%	7.00%
Preferred stock, shares issued	5,400	5,400
Preferred stock, shares outstanding	5,400	5,400
Preferred stock, liquidation preference	$ 135,000	$ 135,000
Class A common stock
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	475,000	475,000
Common stock, shares issued	230,943	236,770
Common stock, shares outstanding	230,943	236,770

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Other Comprehensive (Loss) Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Revenues
Rental income	$ 106,017	$ 115,194	$ 215,991	$ 230,454
Tenant recovery income	29,524	29,654	60,310	60,010
Other property income	1,798	2,378	4,731	5,401
Total revenues	137,339	147,226	281,032	295,865
Expenses
Operating expenses	21,004	20,092	42,868	43,153
Real estate taxes	21,487	21,090	43,366	41,029
Depreciation and amortization	52,325	53,443	105,799	106,839
Provision for impairment of investment properties	13,034	4,142	13,034	6,306
General and administrative expenses	10,370	10,773	21,583	22,179
Total expenses	118,220	109,540	226,650	219,506
Operating income	19,119	37,686	54,382	76,359
Gain on extinguishment of debt	0	0	0	13,653
Gain on extinguishment of other liabilities	0	6,978	0	6,978
Interest expense	(21,435)	(25,977)	(106,967)	(52,741)
Other income, net	451	302	456	427
(Loss) income from continuing operations	(1,865)	18,989	(52,129)	44,676
Gain on sales of investment properties	116,628	9,613	157,792	31,352
Net income	114,763	28,602	105,663	76,028
Preferred stock dividends	(2,363)	(2,363)	(4,725)	(4,725)
Net income attributable to common shareholders	$ 112,400	$ 26,239	$ 100,938	$ 71,303
Earnings per common share – basic and diluted
Net income per common share attributable to common shareholders	$ 0.48	$ 0.11	$ 0.43	$ 0.30
Net income	$ 114,763	$ 28,602	$ 105,663	$ 76,028
Other comprehensive (loss) income:
Net unrealized (loss) gain on derivative instruments (Note 9)	(145)	(510)	487	(477)
Comprehensive income attributable to the Company	$ 114,618	$ 28,092	$ 106,150	$ 75,551
Weighted average number of common shares outstanding – basic	234,243	236,716	235,269	236,647
Weighted average number of common shares outstanding – diluted	234,818	236,902	235,842	236,781

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Equity - USD ($) shares in Thousands, $ in Thousands	Total	Preferred stock7.00% Series A cumulative redeemable preferred stock	Common stockClass A common stock	Additional paid-in capital	Accumulated distributions in excess of earnings	Accumulated other comprehensive (loss) income	Total shareholders' equity
Increase (decrease) in shareholders' equity
Cumulative effect of accounting change				$ 17	$ (17)
Balance at Dec. 31, 2015		$ 5	$ 237	4,931,395	(2,776,215)	$ (85)	$ 2,155,337
Balance (in shares) at Dec. 31, 2015		5,400	237,267
Increase (decrease) in shareholders' equity
Net income	$ 76,028				76,028		76,028
Other comprehensive (loss) income						(477)	(477)
Distributions declared to preferred shareholders					(4,725)		(4,725)
Distributions declared to common shareholders					(78,631)		(78,631)
Issuance of common stock, net of offering costs				(2)			(2)
Issuance of restricted shares (in shares)			269
Stock-based compensation expense, net of forfeitures				3,702			3,702
Stock-based compensation expense, net of forfeitures (in shares)			(6)
Shares withheld for employee taxes				(2,159)			(2,159)
Shares withheld for employee taxes (in shares)			(147)
Balance at Jun. 30, 2016		$ 5	$ 237	4,932,953	(2,783,560)	(562)	2,149,073
Balance (in shares) at Jun. 30, 2016		5,400	237,383
Balance at Dec. 31, 2016	2,152,086	$ 5	$ 237	4,927,155	(2,776,033)	722	2,152,086
Balance (in shares) at Dec. 31, 2016		5,400	236,770
Increase (decrease) in shareholders' equity
Net income	105,663				105,663		105,663
Other comprehensive (loss) income						487	487
Distributions declared to preferred shareholders					(4,725)		(4,725)
Distributions declared to common shareholders					(77,553)		(77,553)
Shares repurchased through share repurchase program			$ (6)	(75,691)			(75,697)
Shares repurchased through share repurchase program (in shares)			(6,024)
Issuance of restricted shares (in shares)			285
Stock-based compensation expense, net of forfeitures				3,549			3,549
Shares withheld for employee taxes				(1,333)			(1,333)
Shares withheld for employee taxes (in shares)			(88)
Balance at Jun. 30, 2017	$ 2,102,477	$ 5	$ 231	$ 4,853,680	$ (2,752,648)	$ 1,209	$ 2,102,477
Balance (in shares) at Jun. 30, 2017		5,400	230,943

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Equity (parenthetical) - $ / shares	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Distributions declared to preferred shareholders (in dollars per share)	$ 0.875	$ 0.875
Distributions declared to common shareholders (in dollars per share)	$ 0.33125	$ 0.33125

Condensed Consolidated Stateme7

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	Jun. 30, 2017	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Cash flows from operating activities:
Net income		$ 114,763	$ 28,602	$ 105,663	$ 76,028
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization				105,799	106,839
Provision for impairment of investment properties		13,034	4,142	13,034	6,306
Gain on sales of investment properties				(157,792)	(31,352)
Gain on extinguishment of debt		0	0	0	(13,653)
Gain on extinguishment of other liabilities		0	(6,978)	0	(6,978)
Amortization of loan fees and debt premium and discount, net				5,871	3,187
Amortization of stock-based compensation				3,549	3,702
Premium paid in connection with defeasance of mortgages payable				59,968	0
Payment of leasing fees and inducements				(9,757)	(5,967)
Changes in accounts receivable, net				4,094	(1,655)
Changes in accounts payable and accrued expenses, net				(15,577)	(11,410)
Changes in other operating assets and liabilities, net				11,388	834
Other, net				(63)	893
Net cash provided by operating activities				126,177	126,774
Cash flows from investing activities:
Changes in restricted escrows, net				17,662	1,769
Purchase of investment properties				(99,434)	(261,877)
Capital expenditures and tenant improvements				(31,629)	(30,216)
Proceeds from sales of investment properties				312,916	41,031
Investment in developments in progress				(8,612)	0
Other, net				0	194
Net cash provided by (used in) investing activities				190,903	(249,099)
Cash flows from financing activities:
Principal payments on mortgages payable				(38,571)	(12,679)
Proceeds from unsecured term loans				200,000	0
Proceeds from unsecured revolving line of credit				474,000	325,000
Repayments of unsecured revolving line of credit				(378,000)	(120,000)
Payment of loan fees and deposits				(10)	(6,043)
Purchase of U.S. Treasury securities in connection with defeasance of mortgages payable				(439,403)	0
Distributions paid				(83,182)	(83,333)
Shares repurchased through share repurchase program				(75,697)	0
Other, net				(1,333)	(2,256)
Net cash (used in) provided by financing activities				(342,196)	100,689
Net decrease in cash and cash equivalents				(25,116)	(21,636)
Cash and cash equivalents, at beginning of period				53,119	51,424	$ 51,424
Cash and cash equivalents, at end of period	$ 28,003	28,003	29,788	28,003	29,788	53,119
Supplemental cash flow disclosure, including non-cash activities:
Cash paid for interest, net of interest capitalized				41,017	46,695
Distributions payable	38,318	38,318	39,320	38,318	39,320	$ 39,222
Accrued capital expenditures and tenant improvements				6,089	8,742
Accrued leasing fees and inducements				840	772
Accrued redevelopment costs				1,019	0
U.S. Treasury securities transferred in connection with defeasance of mortgages payable				439,403	0
Defeasance of mortgages payable				379,435	0
Purchase of investment properties (after credits at closing):
Net investment properties				(101,307)	(257,157)
Accounts receivable, acquired lease intangibles and other assets				(7,659)	(25,049)
Accounts payable, acquired lease intangibles and other liabilities				7,008	5,013
Deferred gain				2,524	0
Mortgages payable assumed, net				0	15,316
Purchase of investment properties (after credits at closing)				(99,434)	(261,877)
Proceeds from sales of investment properties:
Net investment properties				245,853	126,057
Accounts receivable, acquired lease intangibles and other assets				9,766	10,503
Accounts payable, acquired lease intangibles and other liabilities				(6,258)	(3,276)
Deferred gain				(676)	0
Mortgage debt forgiven or assumed				0	(94,353)
Gain on extinguishment of debt		$ 0	$ 0	0	13,653
Gain on sales of investment properties				157,792	31,352
Proceeds temporarily restricted related to potential Internal Revenue Code Section 1031 tax-deferred exchanges	$ (93,561)			(93,561)	(42,905)
Proceeds from sales of investment properties				$ 312,916	$ 41,031

Organization and Basis of Prese

Organization and Basis of Presentation	6 Months Ended
	Jun. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Basis of Presentation	ORGANIZATION AND BASIS OF PRESENTATION Retail Properties of America, Inc. (the Company) was formed on March 5, 2003 and its primary purpose is to own and operate high quality, strategically located shopping centers in the United States. The Company has elected to be taxed as a real estate investment trust (REIT) under the Internal Revenue Code of 1986, as amended (the Code). The Company believes it qualifies for taxation as a REIT and, as such, the Company generally will not be subject to U.S. federal income tax on taxable income that is distributed to its shareholders. If the Company fails to qualify as a REIT in any taxable year, the Company will be subject to U.S. federal income tax on its taxable income. Even if the Company qualifies for taxation as a REIT, the Company may be subject to certain state and local taxes on its income, property or net worth and U.S. federal income and excise taxes on its undistributed income. The Company has one wholly-owned subsidiary that has jointly elected to be treated as a taxable REIT subsidiary (TRS) and is subject to U.S. federal, state and local income taxes at regular corporate tax rates. The income tax expense incurred by the TRS did not have a material impact on the Company’s accompanying condensed consolidated financial statements. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions. These estimates and assumptions affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements and the reported amounts of revenues and expenses during the reporting periods. For example, significant estimates and assumptions have been made with respect to useful lives of assets, capitalization of development costs, fair value measurements, provision for impairment, including estimates of holding periods, capitalization rates and discount rates (where applicable), provision for income taxes, recoverable amounts of receivables, deferred taxes and initial valuations and related amortization periods of deferred costs and intangibles, particularly with respect to property acquisitions. Actual results could differ from these estimates. All share amounts and dollar amounts in this Quarterly Report on Form 10-Q, including the condensed consolidated financial statements and notes thereto, are stated in thousands with the exception of per share amounts and per square foot amounts. The accompanying condensed consolidated financial statements include the accounts of the Company, as well as all wholly-owned subsidiaries and any consolidated variable interest entities (VIEs). All intercompany balances and transactions have been eliminated in consolidation. Wholly-owned subsidiaries generally consist of limited liability companies, limited partnerships and statutory trusts. The Company’s property ownership as of June 30, 2017 is summarized below: Wholly-owned Retail operating properties (a) 132 Office properties 1 Total operating properties 133 Redevelopment properties 2 (a) Excludes four wholly-owned operating properties classified as held for sale as of June 30, 2017 .

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Refer to the Company’s 2016 Annual Report on Form 10-K for a summary of its significant accounting policies. Except as disclosed below, there have been no changes to the Company’s significant accounting policies in the six months ended June 30, 2017 . Recently Adopted Accounting Pronouncements The Company elected to early adopt Financial Accounting Standards Board (FASB) Accounting Standards Update (ASU) 2017-09, Compensation – Stock Compensation , on a prospective basis as of June 30, 2017. This new pronouncement amends/clarifies guidance about which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting. Under the new guidance, an entity should account for the effects of a modification unless all of the following are the same in the modified award as the original award immediately before the original award is modified: 1) the fair value; 2) the vesting conditions; and 3) the classification of the modified award as an equity instrument or a liability instrument. The existing disclosure requirements apply regardless of whether an entity is required to apply modification accounting. The adoption of this pronouncement did not have any effect on the Company’s condensed consolidated financial statements. Recently Issued Accounting Pronouncements In March 2017, the Securities and Exchange Commission issued a final rule, Exhibit Hyperlinks and HTML Format , which is effective September 1, 2017. The final rule will require registrants that file registration statements and reports subject to the exhibit requirements under Item 601 of Regulation S-K, or that file Forms F-10 or 20-F, to include a hyperlink to each exhibit listed in the exhibit index of these filings. To enable the inclusion of such hyperlinks, registrants will be required to submit all such filings in HyperText Markup Language (HTML) format. The Company expects to add hyperlinks to its exhibit index starting with the Form 10-Q for the quarter ended September 30, 2017. In May 2014 with subsequent updates issued in August 2015 and March, April, May and December 2016, the FASB issued ASU 2014-09, Revenue from Contracts with Customers . This new guidance is effective January 1, 2018, with early adoption permitted, and will replace existing revenue recognition standards. The core principle of this standard is that an entity recognizes revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The sale of investment property and any non-lease components contained within lease agreements will be required to follow the new guidance; however, lease components of lease contracts will be subject to the Leases guidance described below. This pronouncement allows either a full or a modified retrospective method of adoption. Expanded quantitative and qualitative disclosures regarding revenue recognition will be required for contracts that are subject to this guidance. While the Company anticipates additional disclosure, it does not expect the adoption of this pronouncement will have a material effect on its condensed consolidated financial statements as it believes the majority of its revenue falls outside of the scope of this guidance; however, it will continue to evaluate this assessment until the guidance becomes effective. The Company is also evaluating whether it will adopt this guidance on a full retrospective basis or a modified retrospective basis. In February 2017, the FASB issued ASU 2017-05, Other Income–Gains and Losses from the Derecognition of Nonfinancial Assets . This new guidance is required to be adopted concurrently with the amendments in ASU 2014-09, Revenue from Contracts with Customers . The new pronouncement, which adds guidance for partial sales of nonfinancial assets and clarifies the scope of Subtopic 610-20, Gains and Losses from the Derecognition of Nonfinancial Assets , applies to the derecognition of all nonfinancial assets (including real estate) for which the counterparty is not a customer. The pronouncement requires either a retrospective or a modified retrospective method of adoption. The Company does not expect the adoption of this pronouncement will have a material effect on its condensed consolidated financial statements; however, it will continue to evaluate this assessment until the guidance becomes effective. In January 2016, the FASB issued ASU 2016-01, Financial Instruments – Overall . This new guidance is effective January 1, 2018 and will require companies to disclose the fair value of financial assets and financial liabilities measured at amortized cost in accordance with the exit price notion and will no longer require disclosure of the methods and significant assumptions used, including any changes, to estimate fair value. In addition, companies will be required to disclose all financial assets and financial liabilities grouped by 1) measurement category and 2) form of financial instrument. The Company does not expect the adoption of this pronouncement will have a material effect on its condensed consolidated financial statements; however, it will continue to evaluate this assessment until the guidance becomes effective. In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows . This new guidance is effective January 1, 2018, with early adoption permitted, and adds or clarifies guidance on the classification of certain cash receipts and payments in the statement of cash flows. Of the eight types of cash flows discussed in the new standard, the classification of debt prepayment costs as a financing outflow will impact the Company’s condensed consolidated statements of cash flows as this item is currently reflected as an operating outflow. The pronouncement requires a retrospective transition method of adoption. The Company does not expect the adoption of this pronouncement will have a material effect on its condensed consolidated financial statements; however, it will continue to evaluate this assessment until the guidance becomes effective. In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows . This new guidance is effective January 1, 2018, with early adoption permitted, and requires amounts that are generally described as restricted cash and restricted cash equivalents to be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. The pronouncement requires a retrospective transition method of adoption. Upon adoption, the Company will include amounts generally described as restricted cash within the beginning-of-period, change and end-of-period total amounts on the statement of cash flows rather than within an activity on the statement of cash flows. In February 2016, the FASB issued ASU 2016-02, Leases . This new guidance is effective January 1, 2019, with early adoption permitted, and will require lessees to recognize a liability to make lease payments and a right-of-use (ROU) asset, initially measured at the present value of lease payments, for both operating and financing leases. For leases with a term of 12 months or less, lessees will be permitted to make an accounting policy election by class of underlying asset to not recognize lease liabilities and lease assets. Upon adoption, the Company will recognize a lease liability and an ROU asset for operating leases where it is the lessee, such as ground leases and office leases. The Company is in the process of evaluating the inputs required to calculate the amounts that will be recorded on its balance sheet for each lease. For leases with a term of 12 months or less, the Company expects to make an accounting policy election by class of underlying asset to not recognize lease liabilities and lease assets. Under this new pronouncement, lessor accounting will be largely unchanged from existing GAAP; however, upon adoption of the Leases guidance, non-lease components of leases, including common area maintenance reimbursements, will be accounted for under the Revenue from Contracts with Customers guidance described above. The pronouncement requires a modified retrospective method of adoption, with some optional practical expedients. The Company expects to adopt this new guidance on January 1, 2019 and will continue to evaluate the impact of this guidance until it becomes effective. In June 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses . This new guidance is effective January 1, 2020, with early adoption permitted beginning January 1, 2019, and replaces the current incurred loss impairment methodology with a methodology that reflects expected credit losses. Financial assets that are measured at amortized cost will be required to be presented at the net amount expected to be collected with an allowance for credit losses deducted from the amortized cost basis. In addition, an entity must consider broader information in developing its expected credit loss estimate, including the use of forecasted information. Generally, the pronouncement requires a modified retrospective method of adoption. The Company will continue to evaluate the impact of this guidance until it becomes effective.

Acquisitions

Acquisitions	6 Months Ended
	Jun. 30, 2017
Business Combinations [Abstract]
Acquisitions	ACQUISITIONS The Company closed on the following acquisitions during the six months ended June 30, 2017: Date Property Name Metropolitan Property Type Square Footage Acquisition Price January 13, 2017 Main Street Promenade (a) Chicago Multi-tenant retail 181,600 $ 88,000 January 25, 2017 Boulevard at the Capital Centre – Fee Interest (b) Washington, D.C. Fee interest (b) — 2,000 February 24, 2017 One Loudoun Downtown – Phase II (c) Washington, D.C. Additional phase of multi-tenant retail (c) 15,900 4,128 April 5, 2017 One Loudoun Downtown – Phase III (c) Washington, D.C. Additional phase of multi-tenant retail (c) 9,800 2,193 May 16, 2017 One Loudoun Downtown – Phase IV (c) Washington, D.C. Development rights (c) — 3,500 207,300 $ 99,821 (d) (a) This property was acquired through a consolidated VIE and was used to facilitate an Internal Revenue Code Section 1031 tax-deferred exchange (1031 Exchange). (b) The wholly-owned multi-tenant retail operating property located in Largo, Maryland was previously subject to an approximately 70 acre long-term ground lease with a third party. The Company completed a transaction whereby it received the fee interest in approximately 50 acres of the underlying land in exchange for which (i) the Company paid $1,939 and (ii) the term of the ground lease with respect to the remaining approximately 20 acres was shortened to nine months . The Company derecognized building and improvements of $11,347 related to the remaining ground lease, recognized the fair value of land received of $15,200 and recorded a deferred gain of $2,524 . The deferred gain will be recognized upon the expiration of the remaining ground lease. The total number of properties in the Company’s portfolio was not affected by this transaction. (c) The Company acquired three additional phases, including the development rights for an additional 123 multi-family units for a total of 408 , at its One Loudoun Downtown multi-tenant retail operating property, which were accounted for as asset acquisitions. The total number of properties in the Company’s portfolio was not affected by these transactions. The remaining phases at One Loudoun Downtown, representing an aggregate gross purchase price of up to $25,700 , are expected to close during the third quarter of 2017 as the seller completes construction on stand-alone buildings at the property. (d) Acquisition price does not include capitalized closing costs and adjustments totaling $2,334 . The Company closed on the following acquisitions during the six months ended June 30, 2016: Date Property Name MSA Property Type Square Footage Acquisition Price January 15, 2016 Shoppes at Hagerstown (a) Hagerstown Multi-tenant retail 113,000 $ 27,055 January 15, 2016 Merrifield Town Center II (a) Washington, D.C. Multi-tenant retail 76,000 45,676 March 29, 2016 Oak Brook Promenade (b) Chicago Multi-tenant retail 183,200 65,954 April 1, 2016 The Shoppes at Union Hill (c) New York Multi-tenant retail 91,700 63,060 April 29, 2016 Ashland & Roosevelt – Fee Interest (d) Chicago Ground lease interest (d) — 13,850 May 5, 2016 Tacoma South (b) Seattle Multi-tenant retail 230,700 39,400 June 15, 2016 Eastside (b) Dallas Multi-tenant retail 67,100 23,842 761,700 $ 278,837 (a) These properties were acquired as a two -property portfolio. Merrifield Town Center II also contains 62,000 square feet of storage space for a total of 138,000 square feet. (b) These properties were acquired through consolidated VIEs and were used to facilitate 1031 Exchanges. (c) In conjunction with the acquisition, the Company assumed mortgage debt with a principal balance of $15,971 and an interest rate of 3.75% that matures in 2031. (d) The Company acquired the fee interest in an existing wholly-owned multi-tenant retail operating property located in Chicago, Illinois, which was previously subject to a ground lease with a third party. In conjunction with this transaction, the Company reversed the straight-line ground rent liability of $6,978 , which is reflected as “Gain on extinguishment of other liabilities” in the accompanying condensed consolidated statements of operations and other comprehensive (loss) income. The following table summarizes the acquisition date values, before prorations, the Company recorded in conjunction with the acquisitions discussed above: Six Months Ended June 30, 2017 2016 Land $ 23,559 $ 84,720 Building and other improvements, net 77,748 172,437 Acquired lease intangible assets (a) 7,343 25,016 Acquired lease intangible liabilities (b) (5,477 ) (3,991 ) Other liabilities (1,076 ) — Mortgages payable, net — (15,316 ) Net assets acquired $ 102,097 $ 262,866 (a) The weighted average amortization period for acquired lease intangible assets is six years for acquisitions completed during the six months ended June 30, 2017 and 2016 . (b) The weighted average amortization period for acquired lease intangible liabilities is 13 years and 11 years for acquisitions completed during the six months ended June 30, 2017 and 2016 , respectively. The above acquisitions were funded using a combination of available cash on hand, proceeds from dispositions and proceeds from the Company’s unsecured revolving line of credit. All of the acquisitions completed during 2017 were considered asset acquisitions and, as such, transaction costs were capitalized upon closing. Transaction costs related to the 2016 acquisitions that were accounted for as business combinations totaled $690 for the six months ended June 30, 2016 and are included in “General and administrative expenses” in the accompanying condensed consolidated statements of operations and other comprehensive (loss) income. In addition, total revenues of $21,802 and net income attributable to common shareholders of $5,011 are included in the Company’s condensed consolidated statements of operations and other comprehensive (loss) income for the six months ended June 30, 2016 from the properties acquired during the six months ended June 30, 2016 that were accounted for as business combinations. Subsequent to June 30, 2017 , the Company acquired New Hyde Park Shopping Center, a 32,300 square foot multi-tenant retail property located in the New York MSA, for a gross purchase price of $22,075 . The Company has not completed the allocation of the acquisition date fair value for this property; however, it expects that this acquisition will be accounted for as an asset acquisition and that the purchase price of this property will primarily be allocated to land, building and acquired lease intangibles. Condensed Pro Forma Financial Information Disclosure of pro forma financial information is required for acquisitions accounted for as business combinations, if such financial information is available. Pro forma financial information is provided for acquisitions accounted for as business combinations completed during the period, or after such period through the financial statement issuance date, as if these acquisitions had been completed as of the beginning of the year prior to the acquisition date. Pro forma financial information is not required for asset acquisitions. The following unaudited condensed pro forma financial information is presented as if the acquisitions completed during the six months ended June 30, 2016 were completed as of January 1, 2015. The acquisition of the fee interest in the Company’s Ashland & Roosevelt multi-tenant retail operating property located in the Chicago MSA, which was acquired on April 29, 2016 for $13,850 , has not been adjusted in the pro forma presentation as it was accounted for as an asset acquisition. Pro forma financial information is not presented for acquisitions completed during 2017 as they have been accounted for as asset acquisitions. These pro forma results are for comparative purposes only and are not necessarily indicative of what the Company’s actual results of operations would have been had the acquisitions occurred at the beginning of the period presented, nor are they necessarily indicative of future operating results. The unaudited condensed pro forma financial information is as follows: Three Months Ended June 30, 2016 Six Months Ended June 30, 2016 Total revenues $ 147,813 $ 300,126 Net income $ 28,559 $ 74,975 Net income attributable to common shareholders $ 26,196 $ 70,250 Earnings per common share – basic and diluted Net income per common share attributable to common shareholders $ 0.11 $ 0.30 Weighted average number of common shares outstanding – basic 236,716 236,647 Variable Interest Entities During the six months ended June 30, 2017 , the Company entered into an agreement with a qualified intermediary related to a potential 1031 Exchange. The Company loaned $87,452 to the VIEs to acquire Main Street Promenade on January 13, 2017. The 1031 Exchange was completed during the three months ended June 30, 2017 and, in accordance with applicable provisions of the Code, within 180 days after the acquisition date of the property. At the completion of the 1031 Exchange, the sole membership interests of the VIEs were assigned to the Company in satisfaction of the outstanding loan, resulting in the entities being wholly owned by the Company and no longer considered VIEs. During the six months ended June 30, 2016 , the Company entered into agreements with a qualified intermediary related to three 1031 Exchanges. The Company loaned $65,419 , $39,215 and $23,522 to acquire Oak Brook Promenade, Tacoma South and Eastside, respectively. Each 1031 Exchange was completed during the year ended December 31, 2016 and, accordingly, no agreements remained outstanding related to 1031 Exchanges as of December 31, 2016. At the completion of the 1031 Exchanges, the sole membership interests of the VIEs were assigned to the Company and the respective outstanding loans were extinguished, resulting in the entities being wholly owned by the Company and no longer considered VIEs. Prior to the completion of the 1031 Exchanges, the Company was deemed to be the primary beneficiary of each VIE as it had the ability to direct the activities of each VIE that most significantly impact its economic performance and had all of the risks and rewards of ownership. Accordingly, the Company consolidated the VIEs. No value or income was attributed to the noncontrolling interest. The assets of the VIEs consisted of the respective investment property, Main Street Promenade, Oak Brook Promenade, Tacoma South and Eastside, which were operated by the Company.

Dispositions

Dispositions	6 Months Ended
	Jun. 30, 2017
Discontinued Operations and Disposal Groups [Abstract]
Dispositions	DISPOSITIONS The Company closed on the following dispositions during the six months ended June 30, 2017: Date Property Name Property Type Square Footage Consideration Aggregate Proceeds, Net (a) Gain January 27, 2017 Rite Aid Store (Eckerd), Culver Rd. – Rochester, NY Single-user retail 10,900 $ 500 $ 332 $ — February 21, 2017 Shoppes at Park West Multi-tenant retail 63,900 15,383 15,261 7,569 March 7, 2017 CVS Pharmacy – Sylacauga, AL (b) Single-user retail 10,100 3,700 16 1,651 March 8, 2017 Rite Aid Store (Eckerd) – Kill Devil Hills, NC Single-user retail 13,800 4,297 4,134 1,857 March 15, 2017 Century III Plaza – Home Depot (c) Single-user parcel 131,900 17,519 17,344 4,487 March 16, 2017 Village Shoppes at Gainesville Multi-tenant retail 229,500 41,750 41,380 14,107 March 24, 2017 Northwood Crossing (b) Multi-tenant retail 160,000 22,850 4 10,007 April 4, 2017 University Town Center (b) Multi-tenant retail 57,500 14,700 (5 ) 9,128 April 4, 2017 Edgemont Town Center (b) Multi-tenant retail 77,700 19,025 (28 ) 8,995 April 4, 2017 Phenix Crossing (b) Multi-tenant retail 56,600 12,400 (28 ) 5,699 April 27, 2017 Brown’s Lane Multi-tenant retail 74,700 10,575 10,318 3,408 May 9, 2017 Rite Aid Store (Eckerd) – Greer, SC Single-user retail 13,800 3,050 2,961 830 May 9, 2017 Evans Towne Centre Multi-tenant retail 75,700 11,825 11,419 5,226 May 25, 2017 Red Bug Village Multi-tenant retail 26,200 8,100 7,767 2,184 May 26, 2017 Wilton Square Multi-tenant retail 438,100 49,300 48,503 19,630 May 30, 2017 Town Square Plaza Multi-tenant retail 215,600 28,600 26,459 3,412 May 31, 2017 Cuyahoga Falls Market Center Multi-tenant retail 76,400 11,500 11,101 1,300 June 5, 2017 Plaza Santa Fe II Multi-tenant retail 224,200 35,220 33,506 16,136 June 6, 2017 Rite Aid Store (Eckerd)–Columbia, SC Single-user retail 13,400 3,250 3,163 1,046 June 16, 2017 Fox Creek Village Multi-tenant retail 107,500 24,825 24,415 12,470 June 29, 2017 Cottage Plaza Multi-tenant retail 85,500 23,050 22,685 8,039 June 29, 2017 Magnolia Square Multi-tenant retail 116,000 16,000 15,692 4,866 June 29, 2017 Cinemark Seven Bridges Single-user retail 70,200 15,271 14,948 3,973 June 29, 2017 Low Country Village I & II (b) Multi-tenant retail 139,900 22,075 (67 ) 10,286 2,489,100 $ 414,765 $ 311,280 $ 156,306 (a) Aggregate proceeds are net of transaction costs and proceeds temporarily restricted related to potential 1031 Exchanges and exclude $150 of condemnation proceeds, which did not result in any additional gain recognition. (b) The following disposition proceeds are temporarily restricted related to potential 1031 Exchanges and are included in “Other assets, net” in the accompanying condensed consolidated balance sheets: Property Name Proceeds Temporarily Restricted CVS Pharmacy – Sylacauga, AL $ 3,332 Northwood Crossing 22,719 University Town Center 14,595 Edgemont Town Center 18,885 Phenix Crossing 12,324 Low Country Village I & II 21,706 $ 93,561 (c) The Company disposed of the Home Depot parcel at Century III Plaza, an existing 284,100 square foot multi-tenant retail operating property. The remaining portion of Century III Plaza is classified as held for sale as of June 30, 2017. During the six months ended June 30, 2017 , the Company also received proceeds and recognized a gain of $1,486 as a result of the receipt of the escrow related to the disposition of Maple Tree Place on August 12, 2016. The aggregate proceeds, net of closing costs and proceeds temporarily restricted related to potential 1031 Exchanges, from property dispositions and other transactions during the six months ended June 30, 2017 totaled $312,916 , with aggregate gains of $157,792 . The Company closed on the following dispositions during the six months ended June 30, 2016: Date Property Name Property Type Square Footage Consideration Aggregate Proceeds, Net (a) Gain February 1, 2016 The Gateway (b) Multi-tenant retail 623,200 $ 75,000 $ (795 ) $ 3,868 February 10, 2016 Stateline Station Multi-tenant retail 142,600 17,500 17,210 4,253 March 30, 2016 Six Property Portfolio (c) Single-user retail 230,400 35,413 12 13,618 April 20, 2016 CVS Pharmacy – Oklahoma City, OK Single-user retail 10,900 4,676 4,608 1,764 June 2, 2016 Rite Aid Store (Eckerd) – Canandaigua, NY & Tim Horton Donut Shop (d) Single-user retail 16,600 5,400 5,333 1,444 June 15, 2016 Academy Sports – Midland, TX (e) Single-user retail 61,200 5,541 17 2,220 June 23, 2016 Four Rite Aid Portfolio (f) Single-user retail 45,400 15,934 14,646 2,287 1,130,300 $ 159,464 $ 41,031 $ 29,454 (a) Aggregate proceeds are net of transaction costs and proceeds temporarily restricted related to potential 1031 Exchanges. (b) The property was disposed of through a lender-directed sale in full satisfaction of the Company’s $94,353 mortgage obligation. Immediately prior to the disposition, the lender reduced the Company’s loan obligation to $75,000 which was assumed by the buyer in connection with the disposition. Along with the loan reduction, the lender received the balance of the restricted escrows that they held and the rights to unpaid accounts receivable and forgave accrued interest, resulting in a net gain on extinguishment of debt of $13,653 . (c) Portfolio consists of the following properties: (i) Academy Sports – Houma, LA, (ii) Academy Sports – Port Arthur, TX, (iii) Academy Sports – San Antonio, TX, (iv) CVS Pharmacy – Moore, OK, (v) CVS Pharmacy – Saginaw, TX and (vi) Rite Aid Store (Eckerd) – Olean, NY. As of June 30, 2016 , disposition proceeds of $34,973 were temporarily restricted related to 1031 Exchanges and are included in “Other assets, net” in the accompanying condensed consolidated balance sheets. (d) The terms of the disposition of Rite Aid Store (Eckerd) – Canandaigua, NY and Tim Horton Donut Shop – Canandaigua, NY were negotiated as a single transaction. (e) As of June 30, 2016 , disposition proceeds of $5,383 were temporarily restricted related to a 1031 Exchange and are included in “Other assets, net” in the accompanying condensed consolidated balance sheets. (f) Portfolio consists of the following properties: (i) Rite Aid Store (Eckerd) – Cheektowaga, NY, (ii) Rite Aid Store (Eckerd), W. Main St. – Batavia, NY, (iii) Rite Aid Store (Eckerd), Union Rd. – West Seneca, NY and (iv) Rite Aid Store (Eckerd) – Greece, NY. During the six months ended June 30, 2016 , the Company disposed of an outparcel for consideration of $2,639 and recorded a gain of $1,898 from the transaction. Disposition proceeds of $2,549 were temporarily restricted related to a 1031 Exchange and are included in “Other assets, net” in the accompanying condensed consolidated balance sheets. The aggregate gains from the property dispositions and this additional transaction totaled $31,352 . None of the dispositions completed during the six months ended June 30, 2017 and 2016 qualified for discontinued operations treatment. The following properties qualified for held for sale accounting treatment prior to or during the quarter ended June 30, 2017 . Upon meeting all applicable GAAP criteria for held for sale accounting treatment, depreciation and amortization were ceased. In addition, the assets and liabilities associated with these properties are separately classified as held for sale in the condensed consolidated balance sheet as of June 30, 2017 . Property Name Property Location Property Type Square Footage Century III Plaza, excluding the Home Depot parcel West Mifflin, Pennsylvania Multi-tenant retail 152,200 Lakepointe Towne Center Lewisville, Texas Multi-tenant retail 196,600 Irmo Station Irmo, South Carolina Multi-tenant retail 99,400 Boulevard Plaza Pawtucket, Rhode Island Multi-tenant retail 111,100 559,300 Subsequent to June 30, 2017 , the Company sold Boulevard Plaza and Irmo Station for total consideration of $30,327 . Century III Plaza, including the Home Depot parcel, and CVS Pharmacy – Sylacauga were classified as held for sale as of December 31, 2016. The Home Depot parcel at Century III Plaza and CVS Pharmacy – Sylacauga were sold during the six months ended June 30, 2017 . The following table presents the assets and liabilities associated with the investment properties classified as held for sale: June 30, 2017 December 31, 2016 Assets Land, building and other improvements $ 54,396 $ 45,395 Less accumulated depreciation (11,852 ) (15,769 ) Net investment properties 42,544 29,626 Other assets 1,543 1,201 Assets associated with investment properties held for sale $ 44,087 $ 30,827 Liabilities Other liabilities $ 1,142 $ 864 Liabilities associated with investment properties held for sale $ 1,142 $ 864 In addition to the dispositions of Boulevard Plaza and Irmo Station, which were classified as held for sale as of June 30, 2017, the Company closed on the disposition of Hickory Ridge, a 380,600 square foot multi-tenant retail operating property, for consideration of $44,020 subsequent to June 30, 2017.

Equity Compensation Plans

Equity Compensation Plans	6 Months Ended
	Jun. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Equity Compensation Plans	EQUITY COMPENSATION PLANS The Company’s 2014 Long-Term Equity Compensation Plan, subject to certain conditions, authorizes the issuance of incentive and non-qualified stock options, restricted stock and restricted stock units, stock appreciation rights and other similar awards as well as cash-based awards to the Company’s employees, non-employee directors, consultants and advisors in connection with compensation and incentive arrangements that may be established by the Company’s board of directors or executive management. The following table summarizes the Company’s unvested restricted shares as of and for the six months ended June 30, 2017 : Unvested Restricted Shares Weighted Average Grant Date Fair Value per Restricted Share Balance as of January 1, 2017 542 $ 15.28 Shares granted (a) 285 $ 14.60 Shares vested (271 ) $ 15.45 Balance as of June 30, 2017 (b) 556 $ 14.85 (a) Shares granted vest over periods ranging from one year to three years in accordance with the terms of applicable award agreements. (b) As of June 30, 2017 , total unrecognized compensation expense related to unvested restricted shares was $4,574 , which is expected to be amortized over a weighted average term of 1.4 years . The following table summarizes the Company’s unvested performance restricted stock units (RSUs) as of and for the six months ended June 30, 2017 : Unvested RSUs Weighted Average Grant Date Fair Value per RSU RSUs eligible for future conversion as of January 1, 2017 391 $ 14.02 RSUs granted (a) 253 $ 15.52 RSUs eligible for future conversion as of June 30, 2017 (b) 644 $ 14.61 (a) Assumptions and inputs as of the grant date included a risk-free interest rate of 1.50% , the Company’s historical common stock performance relative to the peer companies within the National Association of Real Estate Investment Trusts (NAREIT) Shopping Center Index and the Company’s common stock dividend yield of 4.32% . In 2020, following the performance period which concludes on December 31, 2019, one-third of the RSUs that are earned will convert into shares of common stock and two-thirds will convert into restricted shares with a one year vesting term. (b) As of June 30, 2017 , total unrecognized compensation expense related to unvested RSUs was $6,105 , which is expected to be amortized over a weighted average term of 2.7 years . During the three months ended June 30, 2017 and 2016 , the Company recorded compensation expense of $1,756 and $1,676 , respectively, related to unvested restricted shares and RSUs. During the six months ended June 30, 2017 and 2016 , the Company recorded compensation expense of $3,549 and $3,702 , respectively, related to unvested restricted shares and RSUs. The total fair value of restricted shares vested during the six months ended June 30, 2017 was $3,986 . Prior to 2013, non-employee directors had been granted options to acquire shares under the Company’s Third Amended and Restated Independent Director Stock Option and Incentive Plan. As of June 30, 2017 , options to purchase 41 shares of common stock remained outstanding and exercisable. The Company did not grant any options in 2017 or 2016 and did not record any compensation expense related to stock options during the six months ended June 30, 2017 and 2016 .

Mortgages Payable

Mortgages Payable	6 Months Ended
	Jun. 30, 2017
Debt Disclosure [Abstract]
Mortgages Payable	MORTGAGES PAYABLE The following table summarizes the Company’s mortgages payable: June 30, 2017 December 31, 2016 Aggregate Principal Balance Weighted Average Interest Rate Weighted Average Years to Maturity Aggregate Principal Balance Weighted Average Interest Rate Weighted Average Years to Maturity Fixed rate mortgages payable (a) $ 355,389 5.22 % 4.9 $ 773,395 6.31 % 4.2 Premium, net of accumulated amortization 1,223 1,437 Discount, net of accumulated amortization (601 ) (622 ) Capitalized loan fees, net of accumulated amortization (772 ) (5,026 ) Mortgages payable, net $ 355,239 $ 769,184 (a) The fixed rate mortgages had interest rates ranging from 3.75% to 8.00% as of June 30, 2017 and December 31, 2016 . During the six months ended June 30, 2017 , the Company repaid or defeased mortgages payable in the total amount of $415,621 , of which $101,482 related to properties that were disposed of during the period, which had a weighted average fixed interest rate of 7.24% , and made scheduled principal payments of $2,385 related to amortizing loans. Included within the total repayments and defeasances for the six months ended June 30, 2017 is the defeasance of a portfolio of mortgages payable with a principal balance of $379,435 as of December 31, 2016 that was cross-collateralized by 45 properties and scheduled to mature in 2019 (known as the IW JV portfolio of mortgages payable). The Company incurred a defeasance premium and associated fees totaling $60,198 in connection with this transaction, which are included within “Interest expense” in the accompanying condensed consolidated statements of operations and other comprehensive (loss) income. As a result, the 45 properties that secured the mortgages payable as of December 31, 2016 are no longer encumbered by mortgages. Debt Maturities The following table shows the scheduled maturities and principal amortization of the Company’s indebtedness as of June 30, 2017 for the remainder of 2017 , each of the next four years and thereafter and the weighted average interest rates by year. The table does not reflect the impact of any debt activity that occurred after June 30, 2017 . 2017 2018 2019 2020 2021 Thereafter Total Debt: Fixed rate debt: Mortgages payable (a) $ 27,157 $ 5,065 $ 65,352 $ 3,923 $ 22,820 $ 231,072 $ 355,389 Fixed rate term loans (b) — — — — 250,000 200,000 450,000 Unsecured notes payable (c) — — — — 100,000 600,000 700,000 Total fixed rate debt 27,157 5,065 65,352 3,923 372,820 1,031,072 1,505,389 Variable rate debt: Variable rate term loan and revolving line of credit — 200,000 — 182,000 — — 382,000 Total debt (d) $ 27,157 $ 205,065 $ 65,352 $ 185,923 $ 372,820 $ 1,031,072 $ 1,887,389 Weighted average interest rate on debt: Fixed rate debt 4.18 % 5.49 % 7.45 % 4.62 % 2.73 % 4.08 % 3.90 % Variable rate debt (e) — 2.61 % — 2.58 % — — 2.59 % Total 4.18 % 2.68 % 7.45 % 2.62 % 2.73 % 4.08 % 3.64 % (a) Excludes mortgage premium of $1,223 and discount of $(601) , net of accumulated amortization, as of June 30, 2017 . (b) $250,000 of London Interbank Offered Rate (LIBOR)-based variable rate debt has been swapped to a fixed rate through two interest rate swaps. The swaps effectively convert one-month floating rate LIBOR to a weighted average fixed rate of 0.67% through December 31, 2017. In addition, $200,000 of LIBOR-based variable rate debt has been swapped to a fixed rate through two interest rate swaps. The swaps effectively convert one-month floating rate LIBOR to a fixed rate of 1.26% through November 22, 2018. (c) Excludes discount of $(912) , net of accumulated amortization, as of June 30, 2017 . (d) The weighted average years to maturity of consolidated indebtedness was 5.3 years as of June 30, 2017 . Total debt excludes capitalized loan fees of $(7,865) , net of accumulated amortization, as of June 30, 2017 , which are included as a reduction to the respective debt balances. (e) Represents interest rates as of June 30, 2017 . The Company plans on addressing its debt maturities through a combination of proceeds from asset dispositions, capital markets transactions and its unsecured revolving line of credit.

Unsecured Notes Payable

Unsecured Notes Payable	6 Months Ended
	Jun. 30, 2017
Debt Disclosure [Abstract]
Unsecured Notes Payable	UNSECURED NOTES PAYABLE The following table summarizes the Company’s unsecured notes payable: June 30, 2017 December 31, 2016 Unsecured Notes Payable Maturity Date Principal Balance Interest Rate/ Weighted Average Interest Rate Principal Balance Interest Rate/ Weighted Average Interest Rate Senior notes – 4.12% due 2021 June 30, 2021 $ 100,000 4.12 % $ 100,000 4.12 % Senior notes – 4.58% due 2024 June 30, 2024 150,000 4.58 % 150,000 4.58 % Senior notes – 4.00% due 2025 March 15, 2025 250,000 4.00 % 250,000 4.00 % Senior notes – 4.08% due 2026 September 30, 2026 100,000 4.08 % 100,000 4.08 % Senior notes – 4.24% due 2028 December 28, 2028 100,000 4.24 % 100,000 4.24 % 700,000 4.19 % 700,000 4.19 % Discount, net of accumulated amortization (912 ) (971 ) Capitalized loan fees, net of accumulated amortization (3,647 ) (3,886 ) Total $ 695,441 $ 695,143 Notes Due 2026 and 2028 The note purchase agreement governing the 4.08% senior unsecured notes due 2026 and the 4.24% senior unsecured notes due 2028 (Notes Due 2026 and 2028) contains customary covenants and events of default. Pursuant to the terms of the note purchase agreement, the Company is subject to various financial covenants, including the requirement to maintain the following: (i) maximum unencumbered, secured and consolidated leverage ratios; (ii) a minimum interest coverage ratio; (iii) an unencumbered interest coverage ratio (as set forth in the Company’s unsecured credit facility and the note purchase agreement governing the Notes Due 2021 and 2024); and (iv) a fixed charge coverage ratio (as set forth in the Company’s unsecured credit facility). Notes Due 2025 The indenture, as supplemented, governing the 4.00% senior unsecured notes due 2025 (Notes Due 2025) (the Indenture) contains customary covenants and events of default. Pursuant to the terms of the Indenture, the Company is subject to various financial covenants, including the requirement to maintain the following: (i) maximum secured and total leverage ratios; (ii) a debt service coverage ratio; and (iii) maintenance of an unencumbered assets to unsecured debt ratio. Notes Due 2021 and 2024 The note purchase agreement governing the 4.12% senior unsecured notes due 2021 and the 4.58% senior unsecured notes due 2024 (Notes Due 2021 and 2024) contains customary covenants and events of default. Pursuant to the terms of the note purchase agreement, the Company is subject to various financial covenants, some of which are based upon the financial covenants in effect in the Company’s unsecured credit facility, including the requirement to maintain the following: (i) maximum unencumbered, secured and consolidated leverage ratios; (ii) minimum interest coverage and unencumbered interest coverage ratios; and (iii) a minimum consolidated net worth. As of June 30, 2017 , management believes the Company was in compliance with the financial covenants under the Indenture and the note purchase agreements.

Unsecured Term Loans and Revolv

Unsecured Term Loans and Revolving Line of Credit	6 Months Ended
	Jun. 30, 2017
Line of Credit Facility [Abstract]
Unsecured Term Loans and Revolving Line of Credit	UNSECURED TERM LOANS AND REVOLVING LINE OF CREDIT The following table summarizes the Company’s term loans and revolving line of credit: June 30, 2017 December 31, 2016 Maturity Date Balance Interest Rate Balance Interest $250,000 unsecured credit facility term loan – fixed rate (a) January 5, 2021 $ 250,000 1.97 % $ 250,000 1.97 % $200,000 unsecured credit facility term loan – variable rate May 11, 2018 200,000 2.61 % 200,000 2.22 % $200,000 unsecured term loan due 2023 – fixed rate (b) November 22, 2023 200,000 2.96 % — — % Subtotal 650,000 450,000 Capitalized loan fees, net of accumulated amortization (3,446 ) (2,402 ) Term loans, net $ 646,554 $ 447,598 Revolving line of credit – variable rate (c) January 5, 2020 $ 182,000 2.58 % $ 86,000 2.12 % (a) $250,000 of LIBOR -based variable rate debt has been swapped to a weighted average fixed rate of 0.67% plus a credit spread based on a leverage grid ranging from 1.30% to 2.20% through December 31, 2017. The applicable credit spread was 1.30% as of June 30, 2017 and December 31, 2016 . (b) $200,000 of LIBOR -based variable rate debt has been swapped to a fixed rate of 1.26% plus a credit spread based on a leverage grid ranging from 1.70% to 2.55% through November 22, 2018. The applicable credit spread was 1.70% as of June 30, 2017 . (c) Excludes capitalized loan fees, which are included in “Other assets, net” in the accompanying condensed consolidated balance sheets. Unsecured Credit Facility On January 6, 2016, the Company entered into its fourth amended and restated unsecured credit agreement (Unsecured Credit Agreement) with a syndicate of financial institutions led by KeyBank National Association serving as administrative agent and Wells Fargo Bank, National Association serving as syndication agent to provide for an unsecured credit facility aggregating $1,200,000 (Unsecured Credit Facility). The Unsecured Credit Facility consists of a $750,000 unsecured revolving line of credit, a $250,000 unsecured term loan and a $200,000 unsecured term loan and is priced on a leverage grid at a rate of LIBOR plus a credit spread. The Company received investment grade credit ratings from Moody’s and Standard & Poor’s in 2014. In accordance with the unsecured credit agreement, the Company may elect to convert to an investment grade pricing grid. As of June 30, 2017 , making such an election would have resulted in a higher interest rate and, as such, the Company has not made the election to convert to an investment grade pricing grid. The following table summarizes the key terms of the Unsecured Credit Facility: Leverage-Based Pricing Ratings-Based Pricing Unsecured Credit Facility Maturity Date Extension Option Extension Fee Credit Spread Unused Fee Credit Spread Facility Fee $250,000 unsecured term loan 1/5/2021 N/A N/A 1.30% - 2.20% N/A 0.90% - 1.75% N/A $200,000 unsecured term loan 5/11/2018 2 one year 0.15% 1.45% - 2.20% N/A 1.05% - 2.05% N/A $750,000 unsecured revolving line of credit 1/5/2020 2 six month 0.075% 1.35% - 2.25% 0.15% - 0.25% 0.85% - 1.55% 0.125% - 0.30% The Unsecured Credit Facility has a $400,000 accordion option that allows the Company, at its election, to increase the total credit facility up to $1,600,000 , subject to (i) customary fees and conditions including, but not limited to, the absence of an event of default as defined in the Unsecured Credit Agreement and (ii) the Company’s ability to obtain additional lender commitments. The Unsecured Credit Agreement contains customary covenants and events of default. Pursuant to the terms of the Unsecured Credit Agreement, the Company is subject to various financial covenants, including the requirement to maintain the following: (i) maximum unencumbered, secured and consolidated leverage ratios; and (ii) minimum fixed charge and unencumbered interest coverage ratios. As of June 30, 2017 , management believes the Company was in compliance with the financial covenants and default provisions under the Unsecured Credit Agreement. Term Loan Due 2023 On January 3, 2017, the Company received funding on a seven -year $200,000 unsecured term loan with a group of financial institutions, which closed during the year ended December 31, 2016. The Term Loan Due 2023 is priced on a leverage grid at a rate of LIBOR plus a credit spread. In accordance with the term loan agreement (Term Loan Agreement), the Company may elect to convert to an investment grade pricing grid. As of June 30, 2017 , making such an election would have resulted in a higher interest rate and, as such, the Company has not made the election to convert to an investment grade pricing grid. The following table summarizes the key terms of the Term Loan Due 2023: Term Loan Due 2023 Maturity Date Leverage-Based Pricing Credit Spread Ratings-Based Pricing Credit Spread $200,000 unsecured term loan 11/22/2023 1.70% – 2.55% 1.50% – 2.45% The Term Loan Due 2023 has a $100,000 accordion option that allows the Company, at its election, to increase the total unsecured term loan up to $300,000 , subject to customary fees and conditions, including the absence of an event of default as defined in the Term Loan Agreement. The Term Loan Agreement contains customary covenants and events of default, including financial covenants that require the Company to maintain the following: (i) maximum unencumbered, secured and consolidated leverage ratios; and (ii) minimum fixed charge and unencumbered interest coverage ratios. As of June 30, 2017 , management believes the Company was in compliance with the financial covenants and default provisions under the Term Loan Agreement.

Derivatives

Derivatives	6 Months Ended
	Jun. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives	DERIVATIVES The Company’s objective in using interest rate derivatives is to manage its exposure to interest rate movements and add stability to interest expense. To accomplish this objective, the Company uses interest rate swaps as part of its interest rate risk management strategy. Interest rate swaps designated as cash flow hedges involve the receipt of variable rate amounts from a counterparty in exchange for the Company making fixed rate payments over the life of the agreement without exchange of the underlying notional amount. As of June 30, 2017 , the Company utilized four interest rate swaps to hedge the variable cash flows associated with variable rate debt. The effective portion of changes in the fair value of derivatives that are designated and that qualify as cash flow hedges is recorded in “Accumulated other comprehensive income” and is reclassified to interest expense as interest payments are made on the Company’s variable rate debt. Over the next 12 months, the Company estimates that an additional $946 will be reclassified as a decrease to interest expense. The ineffective portion of the change in fair value of derivatives is recognized directly in earnings. The following table summarizes the Company’s interest rate swaps as of June 30, 2017 , which effectively convert one-month floating rate LIBOR to a fixed rate: Effective Date Notional Fixed Interest Rate Termination Date March 1, 2016 $ 100,000 0.66 % December 31, 2017 May 16, 2016 $ 150,000 0.67 % December 31, 2017 January 3, 2017 $ 100,000 1.26 % November 22, 2018 January 3, 2017 $ 100,000 1.26 % November 22, 2018 The following table summarizes the Company’s interest rate swaps that were designated as cash flow hedges of interest rate risk: Number of Instruments Notional Interest Rate Derivatives June 30, 2017 December 31, 2016 June 30, 2017 December 31, 2016 Interest rate swaps 4 2 $ 450,000 $ 250,000 The table below presents the estimated fair value of the Company’s derivative financial instruments, which are presented within “Other assets, net” in the condensed consolidated balance sheets. The valuation techniques utilized are described in Note 13 to the condensed consolidated financial statements. Fair Value June 30, 2017 December 31, 2016 Derivatives designated as cash flow hedges: Interest rate swaps $ 1,219 $ 743 The following table presents the effect of the Company’s derivative financial instruments on the accompanying condensed consolidated statements of operations and other comprehensive (loss) income: Derivatives in Cash Flow Hedging Relationships Amount of Loss (Gain) Recognized in Other Comprehensive Income on Derivative (Effective Portion) Location of (Gain) Loss Reclassified from Accumulated Other Comprehensive Income (AOCI) into Income (Effective Portion) Amount of (Gain) Loss Reclassified from AOCI into Income (Effective Portion) Location of Loss Recognized in Income on Derivative (Ineffective Portion and Amount Excluded from Effectiveness Testing) Amount of Loss Recognized in Income on Derivative (Ineffective Portion and Amount Excluded from Effectiveness Testing) Three Months Six Months Three Months Six Months Three Months Six Months 2017 $ 59 $ (413 ) Interest expense $ (86 ) $ 74 Other income, net $ 5 $ 11 2016 $ 634 $ 687 Interest expense $ 124 $ 210 Other income, net $ 3 $ 3

Equity

Equity	6 Months Ended
	Jun. 30, 2017
Equity [Abstract]
Equity	EQUITY In December 2015, the Company entered into an at-the-market (ATM) equity program under which it may issue and sell shares of its Class A common stock, having an aggregate offering price of up to $250,000 , from time to time. Actual sales may depend on a variety of factors, including, among others, market conditions and the trading price of the Company’s Class A common stock. Any net proceeds are expected to be used for general corporate purposes, which may include the funding of acquisitions and redevelopment activities and the repayment of debt, including the Company’s unsecured revolving line of credit. The Company did not sell any shares under its ATM equity program during the six months ended June 30, 2017 and 2016 . As of June 30, 2017 , the Company had Class A common shares having an aggregate offering price of up to $250,000 remaining available for sale under its ATM equity program. In December 2015, the Company’s board of directors authorized a common stock repurchase program under which the Company may repurchase, from time to time, up to a maximum of $250,000 of shares of its Class A common stock. The shares may be repurchased in the open market or in privately negotiated transactions and are canceled upon repurchase. The timing and actual number of shares repurchased will depend on a variety of factors, including price in absolute terms and in relation to the value of the Company’s assets, corporate and regulatory requirements, market conditions and other corporate liquidity requirements and priorities. The common stock repurchase program may be suspended or terminated at any time without prior notice. The Company did not repurchase any shares during the six months ended June 30, 2016 . During the three and six months ended June 30, 2017 , the Company repurchased 6,024 shares at an average price per share of $12.55 for a total of $75,697 . As of June 30, 2017 , $165,462 remained available under the repurchase program.

Earnings per Share

Earnings per Share	6 Months Ended
	Jun. 30, 2017
Earnings Per Share [Abstract]
Earnings per Share	EARNINGS PER SHARE The following table summarizes the components used in the calculation of basic and diluted earnings per share (EPS): Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 Numerator: (Loss) income from continuing operations $ (1,865 ) $ 18,989 $ (52,129 ) $ 44,676 Gain on sales of investment properties 116,628 9,613 157,792 31,352 Preferred stock dividends (2,363 ) (2,363 ) (4,725 ) (4,725 ) Net income attributable to common shareholders 112,400 26,239 100,938 71,303 Distributions paid on unvested restricted shares (88 ) (110 ) (178 ) (240 ) Net income attributable to common shareholders excluding amounts attributable to unvested restricted shares $ 112,312 $ 26,129 $ 100,760 $ 71,063 Denominator: Denominator for earnings per common share – basic: Weighted average number of common shares outstanding 234,243 (a) 236,716 (b) 235,269 (a) 236,647 (b) Effect of dilutive securities: Stock options 1 (c) 2 (c) 1 (c) 2 (c) RSUs 574 (d) 184 (e) 572 (d) 132 (e) Denominator for earnings per common share – diluted: Weighted average number of common and common equivalent shares outstanding 234,818 236,902 235,842 236,781 (a) Excludes 556 shares of unvested restricted common stock as of June 30, 2017 , which equate to 536 and 550 shares, respectively, on a weighted average basis for the three and six months ended June 30, 2017 . These shares will continue to be excluded from the computation of basic EPS until contingencies are resolved and the shares are released. (b) Excludes 607 shares of unvested restricted common stock as of June 30, 2016 , which equate to 649 and 687 shares, respectively, on a weighted average basis for the three and six months ended June 30, 2016 . These shares were excluded from the computation of basic EPS as the contingencies remained and the shares had not been released as of the end of the reporting period. (c) There were outstanding options to purchase 41 and 53 shares of common stock as of June 30, 2017 and 2016 , respectively, at a weighted average exercise price of $19.25 and $19.39 , respectively. Of these totals, outstanding options to purchase 35 and 45 shares of common stock as of June 30, 2017 and 2016 , respectively, at a weighted average exercise price of $20.55 and $20.74 , respectively, have been excluded from the common shares used in calculating diluted EPS as including them would be anti-dilutive. (d) As of June 30, 2017 , there were 644 RSUs eligible for future conversion upon completion of the performance periods (see Note 5 to the condensed consolidated financial statements), which equate to 644 and 641 RSUs on a weighted average basis for the three and six months ended June 30, 2017 , respectively. These contingently issuable shares are included in diluted EPS based on the weighted average number of shares that would be outstanding during the period, if any, assuming June 30, 2017 was the end of the contingency periods. (e) As of June 30, 2016 , there were 391 RSUs eligible for future conversion upon completion of the performance periods, which equate to 411 and 344 RSUs on a weighted average basis for the three and six months ended June 30, 2016 , respectively. These contingently issuable shares are included in diluted EPS based on the weighted average number of shares that would have been outstanding during the period, if any, assuming June 30, 2016 was the end of the contingency periods.

Provision for Impairment of Inv

Provision for Impairment of Investment Properties	6 Months Ended
	Jun. 30, 2017
Impairment or Disposal of Tangible Assets Disclosure [Abstract]
Provision for Impairment of Investment Properties	PROVISION FOR IMPAIRMENT OF INVESTMENT PROPERTIES As of June 30, 2017 and 2016 , the Company identified indicators of impairment at certain of its properties. Such indicators included a low occupancy rate, difficulty in leasing space and related cost of re-leasing, financially troubled tenants or reduced anticipated holding periods. The following table summarizes the results of these analyses as of June 30, 2017 and 2016 : June 30, 2017 June 30, 2016 Number of properties for which indicators of impairment were identified 7 (a) 6 (b) Less: number of properties for which an impairment charge was recorded 2 1 Less: number of properties that were held for sale as of the date the analysis was performed for which indicators of impairment were identified but no impairment charge was recorded 2 2 Remaining properties for which indicators of impairment were identified but no impairment charge was considered necessary 3 3 Weighted average percentage by which the projected undiscounted cash flows exceeded its respective carrying value for each of the remaining properties (c) 11 % 70 % (a) Includes two properties which were sold subsequent to June 30, 2017 . (b) Includes three properties which have subsequently been sold as of June 30, 2017 . (c) Based upon the estimated holding period for each asset where an undiscounted cash flow analysis was performed. The Company recorded the following investment property impairment charges during the six months ended June 30, 2017 : Property Name Property Type Impairment Date Square Footage Provision for Impairment of Investment Properties Century III Plaza, excluding the Home Depot parcel (a) Multi-tenant retail June 30, 2017 152,200 $ 3,076 Lakepointe Towne Center (b) Multi-tenant retail June 30, 2017 196,600 9,958 $ 13,034 Estimated fair value of impaired properties as of impairment date $ 22,500 (a) The Company recorded an impairment charge based upon the terms and conditions of a bona fide purchase offer. This property was classified as held for sale as of June 30, 2017. The Home Depot parcel of Century III Plaza was sold on March 15, 2017. (b) The Company recorded an impairment charge based upon the terms and conditions of an executed sales contract. This property was classified as held for sale as of June 30, 2017. The Company recorded the following investment property impairment charges during the six months ended June 30, 2016 : Property Name Property Type Impairment Date Square Footage Provision for Impairment of Investment Properties South Billings Center (a) Development March 31, 2016 — $ 2,164 Mid-Hudson Center (b) Multi-tenant retail June 30, 2016 235,600 4,142 $ 6,306 Estimated fair value of impaired properties as of impairment date $ 30,500 (a) An impairment charge was recorded on March 31, 2016 based upon the terms and conditions of an executed sales contract, which was subsequently terminated. The property, which was not under active development, was sold on December 16, 2016 and additional impairment was recognized pursuant to the terms and conditions of an executed sales contract. (b) The Company recorded an impairment charge based upon the terms and conditions of an executed sales contract. This property was classified as held for sale as of June 30, 2016 and was sold on July 21, 2016. The Company provides no assurance that material impairment charges with respect to its investment properties will not occur in future periods.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTS Fair Value of Financial Instruments The following table presents the carrying value and estimated fair value of the Company’s financial instruments: June 30, 2017 December 31, 2016 Carrying Value Fair Value Carrying Value Fair Value Financial assets: Derivative asset $ 1,219 $ 1,219 $ 743 $ 743 Financial liabilities: Mortgages payable, net $ 355,239 $ 373,975 $ 769,184 $ 833,210 Unsecured notes payable, net $ 695,441 $ 692,274 $ 695,143 $ 679,212 Unsecured term loans, net $ 646,554 $ 650,273 $ 447,598 $ 450,421 Unsecured revolving line of credit $ 182,000 $ 182,231 $ 86,000 $ 86,130 The carrying value of the derivative asset is included in “Other assets, net” in the accompanying condensed consolidated balance sheets. Recurring Fair Value Measurements The following table presents the Company’s financial instruments, which are measured at fair value on a recurring basis, by the level in the fair value hierarchy within which those measurements fall. Methods and assumptions used to estimate the fair value of these instruments are described after the table. Fair Value Level 1 Level 2 Level 3 Total June 30, 2017 Derivative asset $ — $ 1,219 $ — $ 1,219 December 31, 2016 Derivative asset $ — $ 743 $ — $ 743 Derivative asset: The fair value of the derivative asset is determined using a discounted cash flow analysis on the expected future cash flows of each derivative. This analysis utilizes observable market data including forward yield curves and implied volatilities to determine the market’s expectation of the future cash flows of the variable component. The fixed and variable components of the derivative are then discounted using calculated discount factors developed based on the LIBOR swap rate and are aggregated to arrive at a single valuation for the period. The Company also incorporates credit valuation adjustments to appropriately reflect both its own nonperformance risk and the respective counterparty’s nonperformance risk in the fair value measurements. Although the Company has determined that the majority of the inputs used to value its derivatives fall within Level 2 of the fair value hierarchy, the credit valuation adjustments associated with its derivatives utilize Level 3 inputs, such as estimates of current credit spreads to evaluate the likelihood of default by itself and its counterparties. However, as of June 30, 2017 and December 31, 2016 , the Company has assessed the significance of the impact of the credit valuation adjustments on the overall valuation of its derivative positions and has determined that the credit valuation adjustments are not significant to the overall valuation. As a result, the Company has determined that its derivative valuations in their entirety are classified within Level 2 of the fair value hierarchy. In adjusting the fair value of its derivative contracts for the effect of nonperformance risk, the Company has considered any applicable credit enhancements. The Company’s derivative instruments are further described in Note 9 to the condensed consolidated financial statements. Nonrecurring Fair Value Measurements The following table presents the Company’s assets remeasured at fair value on a nonrecurring basis as of June 30, 2017 and December 31, 2016, aggregated by the level within the fair value hierarchy in which those measurements fall. The table includes information related to properties remeasured to fair value as a result of impairment charges recorded during the six months ended June 30, 2017 and the year ended December 31, 2016, except for those properties sold prior to June 30, 2017 and December 31, 2016, respectively. Methods and assumptions used to estimate the fair value of these assets are described after the table. Fair Value Level 1 Level 2 Level 3 Total Provision for Impairment (a) June 30, 2017 Investment properties – held for sale $ — $ 22,500 (b) $ — $ 22,500 $ 13,034 December 31, 2016 Investment properties $ — $ 500 (c) $ 10,600 (d) $ 11,100 $ 13,227 (a) Excludes impairment charges recorded on investment properties sold prior to June 30, 2017 and December 31, 2016, respectively. (b) Represents the fair values of the Company’s Century III Plaza and Lakepointe Towne Center investment properties. The estimated fair value of Century III Plaza of $12,000 was based upon the expected sales price from a bona fide purchase offer and determined to be a Level 2 input. The estimated fair value of Lakepointe Towne Center of $10,500 was based upon the expected sales price from an executed sales contract and determined to be a Level 2 input. (c) Represents the fair value of the Company’s Rite Aid Store (Eckerd), Culver Rd. investment property. The estimated fair value of Rite Aid Store (Eckerd), Culver Rd. was based upon the expected sales price from a bona fide purchase offer and determined to be a Level 2 input. (d) Represents the fair values of the Company’s Crown Theater and Saucon Valley Square investment properties. The estimated fair values of Crown Theater and Saucon Valley Square of $4,000 and $6,600 , respectively, were determined using the income approach. The income approach involves discounting the estimated income stream and reversion (presumed sale) value of a property over an estimated holding period to a present value at a risk-adjusted rate. Discount rates, growth assumptions and terminal capitalization rates utilized in this approach are derived from property-specific information, market transactions and other financial and industry data. The terminal capitalization rate and discount rate are significant inputs to this valuation. The following were the key Level 3 inputs used in estimating the fair values of Crown Theater as of December 31, 2016 and Saucon Valley Square as of September 30, 2016, the date the assets were measured at fair value: 2016 Low High Rental revenue growth rates Varies (i) Varies (i) Operating expense growth rates 3.10% 18.02% Discount rates 9.35% 10.00% Terminal capitalization rates 8.35% 9.50% (i) Since cash flow models are established at the tenant level, projected rental revenue growth rates fluctuate over the course of the estimated holding period based upon the timing of lease rollover, amount of available space and other property and space-specific factors. Fair Value Disclosures The following table presents the Company’s financial liabilities, which are measured at fair value for disclosure purposes, by the level in the fair value hierarchy within which those measurements fall. Methods and assumptions used to estimate the fair value of these instruments are described after the table. Fair Value Level 1 Level 2 Level 3 Total June 30, 2017 Mortgages payable, net $ — $ — $ 373,975 $ 373,975 Unsecured notes payable, net $ 244,308 $ — $ 447,966 $ 692,274 Unsecured term loans, net $ — $ — $ 650,273 $ 650,273 Unsecured revolving line of credit $ — $ — $ 182,231 $ 182,231 December 31, 2016 Mortgages payable, net $ — $ — $ 833,210 $ 833,210 Unsecured notes payable, net $ 234,700 $ — $ 444,512 $ 679,212 Unsecured term loans, net $ — $ — $ 450,421 $ 450,421 Unsecured revolving line of credit $ — $ — $ 86,130 $ 86,130 Mortgages payable, net: The Company estimates the fair value of its mortgages payable by discounting the anticipated future cash flows of each instrument at rates currently offered to the Company by its lenders for similar debt instruments of comparable maturities. The rates used are not directly observable in the marketplace and judgment is used in determining the appropriate rate for each of the Company’s individual mortgages payable based upon the specific terms of the agreement, including the term to maturity, the quality and nature of the underlying property and its leverage ratio. The rates used range from 2.9% to 4.2% and 2.9% to 4.6% as of June 30, 2017 and December 31, 2016 , respectively. Unsecured notes payable, net: The quoted market price as of June 30, 2017 was used to value the Notes Due 2025. The Company estimates the fair value of its Notes Due 2021 and 2024 and Notes Due 2026 and 2028 by discounting the future cash flows at rates currently offered to the Company by its lenders for similar debt instruments of comparable maturities. The rates used are not directly observable in the marketplace and judgment is used in determining the appropriate rates. The weighted average rates used were 4.35% and 4.48% as of June 30, 2017 and December 31, 2016 , respectively. Unsecured term loans, net: The Company estimates the fair value of its unsecured term loans, net by discounting the anticipated future cash flows related to the credit spreads at rates currently offered to the Company by its lenders for similar instruments of comparable maturities. The rates used are not directly observable in the marketplace and judgment is used in determining the appropriate rates. The weighted average rates used to discount the credit spreads were 1.42% and 1.30% as of June 30, 2017 and December 31, 2016 , respectively. Unsecured revolving line of credit: The Company estimates the fair value of its unsecured revolving line of credit by discounting the anticipated future cash flows related to the credit spreads at rates currently offered to the Company by its lenders for similar facilities of comparable maturity. The rates used are not directly observable in the marketplace and judgment is used in determining the appropriate rates. The rate used to discount the credit spreads was 1.30% as of June 30, 2017 and December 31, 2016 . There were no transfers between the levels of the fair value hierarchy during the six months ended June 30, 2017 .

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES As of June 30, 2017 , the Company had letter(s) of credit outstanding totaling $13,159 which serve as collateral for certain capital improvements and performance obligations on certain redevelopment projects, which will be satisfied upon completion of the projects, and reduced the available borrowings on its unsecured revolving line of credit. As of June 30, 2017 , the Company had begun redevelopment activities at Reisterstown Road Plaza located in Baltimore, Maryland and Towson Circle located in Towson, Maryland. The Company estimates that it will incur net costs of approximately $9,500 to $10,500 related to the Reisterstown Road Plaza redevelopment and approximately $33,000 to $35,000 related to the Towson Circle redevelopment, of which $4,857 and $11,207 , respectively, has been incurred as of June 30, 2017 .

Litigation

Litigation	6 Months Ended
	Jun. 30, 2017
Litigation Disclosure [Abstract]
Legal Matters and Contingencies	LITIGATION The Company is subject, from time to time, to various legal proceedings and claims that arise in the ordinary course of business. While the resolution of such matters cannot be predicted with certainty, management believes, based on currently available information, that the final outcome of such matters will not have a material effect on the Company’s condensed consolidated financial statements.

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2017
Subsequent Events [Abstract]
Subsequent Events	SUBSEQUENT EVENTS Subsequent to June 30, 2017 , the Company: • closed on the acquisition of New Hyde Park Shopping Center, a 32,300 square foot multi-tenant retail property located in New Hyde Park, New York, for a gross purchase price of $22,075 ; • closed on the disposition of Boulevard Plaza, a 111,100 square foot multi-tenant retail operating property located in Pawtucket, Rhode Island, which was classified as held for sale as of June 30, 2017, for a sales price of $14,300 with an anticipated gain on sale; • closed on the disposition of Irmo Station, a 99,400 square foot multi-tenant retail operating property located in Irmo, South Carolina, which was classified as held for sale as of June 30, 2017, for a sales price of $16,027 with an anticipated gain on sale; • closed on the disposition of Hickory Ridge, a 380,600 square foot multi-tenant retail operating property located in Hickory, North Carolina, for a sales price of $44,020 with an anticipated gain on sale; • declared the cash dividend for the third quarter of 2017 for its 7.00% Series A cumulative redeemable preferred stock. The dividend of $0.4375 per preferred share will be paid on October 2, 2017 to preferred shareholders of record at the close of business on September 21, 2017; and • declared the cash dividend for the third quarter of 2017 of $0.165625 per share on its outstanding Class A common stock, which will be paid on October 10, 2017 to Class A common shareholders of record at the close of business on September 26, 2017.

Summary of Significant Accoun24

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2017
Accounting Policies [Abstract]
Recent Accounting Pronouncements	Recently Issued Accounting Pronouncements In March 2017, the Securities and Exchange Commission issued a final rule, Exhibit Hyperlinks and HTML Format , which is effective September 1, 2017. The final rule will require registrants that file registration statements and reports subject to the exhibit requirements under Item 601 of Regulation S-K, or that file Forms F-10 or 20-F, to include a hyperlink to each exhibit listed in the exhibit index of these filings. To enable the inclusion of such hyperlinks, registrants will be required to submit all such filings in HyperText Markup Language (HTML) format. The Company expects to add hyperlinks to its exhibit index starting with the Form 10-Q for the quarter ended September 30, 2017. In May 2014 with subsequent updates issued in August 2015 and March, April, May and December 2016, the FASB issued ASU 2014-09, Revenue from Contracts with Customers . This new guidance is effective January 1, 2018, with early adoption permitted, and will replace existing revenue recognition standards. The core principle of this standard is that an entity recognizes revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The sale of investment property and any non-lease components contained within lease agreements will be required to follow the new guidance; however, lease components of lease contracts will be subject to the Leases guidance described below. This pronouncement allows either a full or a modified retrospective method of adoption. Expanded quantitative and qualitative disclosures regarding revenue recognition will be required for contracts that are subject to this guidance. While the Company anticipates additional disclosure, it does not expect the adoption of this pronouncement will have a material effect on its condensed consolidated financial statements as it believes the majority of its revenue falls outside of the scope of this guidance; however, it will continue to evaluate this assessment until the guidance becomes effective. The Company is also evaluating whether it will adopt this guidance on a full retrospective basis or a modified retrospective basis. In February 2017, the FASB issued ASU 2017-05, Other Income–Gains and Losses from the Derecognition of Nonfinancial Assets . This new guidance is required to be adopted concurrently with the amendments in ASU 2014-09, Revenue from Contracts with Customers . The new pronouncement, which adds guidance for partial sales of nonfinancial assets and clarifies the scope of Subtopic 610-20, Gains and Losses from the Derecognition of Nonfinancial Assets , applies to the derecognition of all nonfinancial assets (including real estate) for which the counterparty is not a customer. The pronouncement requires either a retrospective or a modified retrospective method of adoption. The Company does not expect the adoption of this pronouncement will have a material effect on its condensed consolidated financial statements; however, it will continue to evaluate this assessment until the guidance becomes effective. In January 2016, the FASB issued ASU 2016-01, Financial Instruments – Overall . This new guidance is effective January 1, 2018 and will require companies to disclose the fair value of financial assets and financial liabilities measured at amortized cost in accordance with the exit price notion and will no longer require disclosure of the methods and significant assumptions used, including any changes, to estimate fair value. In addition, companies will be required to disclose all financial assets and financial liabilities grouped by 1) measurement category and 2) form of financial instrument. The Company does not expect the adoption of this pronouncement will have a material effect on its condensed consolidated financial statements; however, it will continue to evaluate this assessment until the guidance becomes effective. In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows . This new guidance is effective January 1, 2018, with early adoption permitted, and adds or clarifies guidance on the classification of certain cash receipts and payments in the statement of cash flows. Of the eight types of cash flows discussed in the new standard, the classification of debt prepayment costs as a financing outflow will impact the Company’s condensed consolidated statements of cash flows as this item is currently reflected as an operating outflow. The pronouncement requires a retrospective transition method of adoption. The Company does not expect the adoption of this pronouncement will have a material effect on its condensed consolidated financial statements; however, it will continue to evaluate this assessment until the guidance becomes effective. In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows . This new guidance is effective January 1, 2018, with early adoption permitted, and requires amounts that are generally described as restricted cash and restricted cash equivalents to be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. The pronouncement requires a retrospective transition method of adoption. Upon adoption, the Company will include amounts generally described as restricted cash within the beginning-of-period, change and end-of-period total amounts on the statement of cash flows rather than within an activity on the statement of cash flows. In February 2016, the FASB issued ASU 2016-02, Leases . This new guidance is effective January 1, 2019, with early adoption permitted, and will require lessees to recognize a liability to make lease payments and a right-of-use (ROU) asset, initially measured at the present value of lease payments, for both operating and financing leases. For leases with a term of 12 months or less, lessees will be permitted to make an accounting policy election by class of underlying asset to not recognize lease liabilities and lease assets. Upon adoption, the Company will recognize a lease liability and an ROU asset for operating leases where it is the lessee, such as ground leases and office leases. The Company is in the process of evaluating the inputs required to calculate the amounts that will be recorded on its balance sheet for each lease. For leases with a term of 12 months or less, the Company expects to make an accounting policy election by class of underlying asset to not recognize lease liabilities and lease assets. Under this new pronouncement, lessor accounting will be largely unchanged from existing GAAP; however, upon adoption of the Leases guidance, non-lease components of leases, including common area maintenance reimbursements, will be accounted for under the Revenue from Contracts with Customers guidance described above. The pronouncement requires a modified retrospective method of adoption, with some optional practical expedients. The Company expects to adopt this new guidance on January 1, 2019 and will continue to evaluate the impact of this guidance until it becomes effective. In June 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses . This new guidance is effective January 1, 2020, with early adoption permitted beginning January 1, 2019, and replaces the current incurred loss impairment methodology with a methodology that reflects expected credit losses. Financial assets that are measured at amortized cost will be required to be presented at the net amount expected to be collected with an allowance for credit losses deducted from the amortized cost basis. In addition, an entity must consider broader information in developing its expected credit loss estimate, including the use of forecasted information. Generally, the pronouncement requires a modified retrospective method of adoption. The Company will continue to evaluate the impact of this guidance until it becomes effective.

Organization and Basis of Pre25

Organization and Basis of Presentation (Tables)	6 Months Ended
	Jun. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Summary of property ownership	The Company’s property ownership as of June 30, 2017 is summarized below: Wholly-owned Retail operating properties (a) 132 Office properties 1 Total operating properties 133 Redevelopment properties 2 (a) Excludes four wholly-owned operating properties classified as held for sale as of June 30, 2017 .

Acquisitions (Tables)

Acquisitions (Tables)	6 Months Ended
	Jun. 30, 2017
Business Combinations [Abstract]
Schedule of acquisitions	The Company closed on the following acquisitions during the six months ended June 30, 2017: Date Property Name Metropolitan Property Type Square Footage Acquisition Price January 13, 2017 Main Street Promenade (a) Chicago Multi-tenant retail 181,600 $ 88,000 January 25, 2017 Boulevard at the Capital Centre – Fee Interest (b) Washington, D.C. Fee interest (b) — 2,000 February 24, 2017 One Loudoun Downtown – Phase II (c) Washington, D.C. Additional phase of multi-tenant retail (c) 15,900 4,128 April 5, 2017 One Loudoun Downtown – Phase III (c) Washington, D.C. Additional phase of multi-tenant retail (c) 9,800 2,193 May 16, 2017 One Loudoun Downtown – Phase IV (c) Washington, D.C. Development rights (c) — 3,500 207,300 $ 99,821 (d) (a) This property was acquired through a consolidated VIE and was used to facilitate an Internal Revenue Code Section 1031 tax-deferred exchange (1031 Exchange). (b) The wholly-owned multi-tenant retail operating property located in Largo, Maryland was previously subject to an approximately 70 acre long-term ground lease with a third party. The Company completed a transaction whereby it received the fee interest in approximately 50 acres of the underlying land in exchange for which (i) the Company paid $1,939 and (ii) the term of the ground lease with respect to the remaining approximately 20 acres was shortened to nine months . The Company derecognized building and improvements of $11,347 related to the remaining ground lease, recognized the fair value of land received of $15,200 and recorded a deferred gain of $2,524 . The deferred gain will be recognized upon the expiration of the remaining ground lease. The total number of properties in the Company’s portfolio was not affected by this transaction. (c) The Company acquired three additional phases, including the development rights for an additional 123 multi-family units for a total of 408 , at its One Loudoun Downtown multi-tenant retail operating property, which were accounted for as asset acquisitions. The total number of properties in the Company’s portfolio was not affected by these transactions. The remaining phases at One Loudoun Downtown, representing an aggregate gross purchase price of up to $25,700 , are expected to close during the third quarter of 2017 as the seller completes construction on stand-alone buildings at the property. (d) Acquisition price does not include capitalized closing costs and adjustments totaling $2,334 . The Company closed on the following acquisitions during the six months ended June 30, 2016: Date Property Name MSA Property Type Square Footage Acquisition Price January 15, 2016 Shoppes at Hagerstown (a) Hagerstown Multi-tenant retail 113,000 $ 27,055 January 15, 2016 Merrifield Town Center II (a) Washington, D.C. Multi-tenant retail 76,000 45,676 March 29, 2016 Oak Brook Promenade (b) Chicago Multi-tenant retail 183,200 65,954 April 1, 2016 The Shoppes at Union Hill (c) New York Multi-tenant retail 91,700 63,060 April 29, 2016 Ashland & Roosevelt – Fee Interest (d) Chicago Ground lease interest (d) — 13,850 May 5, 2016 Tacoma South (b) Seattle Multi-tenant retail 230,700 39,400 June 15, 2016 Eastside (b) Dallas Multi-tenant retail 67,100 23,842 761,700 $ 278,837 (a) These properties were acquired as a two -property portfolio. Merrifield Town Center II also contains 62,000 square feet of storage space for a total of 138,000 square feet. (b) These properties were acquired through consolidated VIEs and were used to facilitate 1031 Exchanges. (c) In conjunction with the acquisition, the Company assumed mortgage debt with a principal balance of $15,971 and an interest rate of 3.75% that matures in 2031. (d) The Company acquired the fee interest in an existing wholly-owned multi-tenant retail operating property located in Chicago, Illinois, which was previously subject to a ground lease with a third party. In conjunction with this transaction, the Company reversed the straight-line ground rent liability of $6,978 , which is reflected as “Gain on extinguishment of other liabilities” in the accompanying condensed consolidated statements of operations and other comprehensive (loss) income.
Schedule of acquisition date fair values	The following table summarizes the acquisition date values, before prorations, the Company recorded in conjunction with the acquisitions discussed above: Six Months Ended June 30, 2017 2016 Land $ 23,559 $ 84,720 Building and other improvements, net 77,748 172,437 Acquired lease intangible assets (a) 7,343 25,016 Acquired lease intangible liabilities (b) (5,477 ) (3,991 ) Other liabilities (1,076 ) — Mortgages payable, net — (15,316 ) Net assets acquired $ 102,097 $ 262,866 (a) The weighted average amortization period for acquired lease intangible assets is six years for acquisitions completed during the six months ended June 30, 2017 and 2016 . (b) The weighted average amortization period for acquired lease intangible liabilities is 13 years and 11 years for acquisitions completed during the six months ended June 30, 2017 and 2016 , respectively.
Schedule of condensed pro forma financial information	The unaudited condensed pro forma financial information is as follows: Three Months Ended June 30, 2016 Six Months Ended June 30, 2016 Total revenues $ 147,813 $ 300,126 Net income $ 28,559 $ 74,975 Net income attributable to common shareholders $ 26,196 $ 70,250 Earnings per common share – basic and diluted Net income per common share attributable to common shareholders $ 0.11 $ 0.30 Weighted average number of common shares outstanding – basic 236,716 236,647

Dispositions (Tables)

Dispositions (Tables)	6 Months Ended
	Jun. 30, 2017
Discontinued Operations and Disposal Groups [Abstract]
Schedule of property dispositions	The Company closed on the following dispositions during the six months ended June 30, 2017: Date Property Name Property Type Square Footage Consideration Aggregate Proceeds, Net (a) Gain January 27, 2017 Rite Aid Store (Eckerd), Culver Rd. – Rochester, NY Single-user retail 10,900 $ 500 $ 332 $ — February 21, 2017 Shoppes at Park West Multi-tenant retail 63,900 15,383 15,261 7,569 March 7, 2017 CVS Pharmacy – Sylacauga, AL (b) Single-user retail 10,100 3,700 16 1,651 March 8, 2017 Rite Aid Store (Eckerd) – Kill Devil Hills, NC Single-user retail 13,800 4,297 4,134 1,857 March 15, 2017 Century III Plaza – Home Depot (c) Single-user parcel 131,900 17,519 17,344 4,487 March 16, 2017 Village Shoppes at Gainesville Multi-tenant retail 229,500 41,750 41,380 14,107 March 24, 2017 Northwood Crossing (b) Multi-tenant retail 160,000 22,850 4 10,007 April 4, 2017 University Town Center (b) Multi-tenant retail 57,500 14,700 (5 ) 9,128 April 4, 2017 Edgemont Town Center (b) Multi-tenant retail 77,700 19,025 (28 ) 8,995 April 4, 2017 Phenix Crossing (b) Multi-tenant retail 56,600 12,400 (28 ) 5,699 April 27, 2017 Brown’s Lane Multi-tenant retail 74,700 10,575 10,318 3,408 May 9, 2017 Rite Aid Store (Eckerd) – Greer, SC Single-user retail 13,800 3,050 2,961 830 May 9, 2017 Evans Towne Centre Multi-tenant retail 75,700 11,825 11,419 5,226 May 25, 2017 Red Bug Village Multi-tenant retail 26,200 8,100 7,767 2,184 May 26, 2017 Wilton Square Multi-tenant retail 438,100 49,300 48,503 19,630 May 30, 2017 Town Square Plaza Multi-tenant retail 215,600 28,600 26,459 3,412 May 31, 2017 Cuyahoga Falls Market Center Multi-tenant retail 76,400 11,500 11,101 1,300 June 5, 2017 Plaza Santa Fe II Multi-tenant retail 224,200 35,220 33,506 16,136 June 6, 2017 Rite Aid Store (Eckerd)–Columbia, SC Single-user retail 13,400 3,250 3,163 1,046 June 16, 2017 Fox Creek Village Multi-tenant retail 107,500 24,825 24,415 12,470 June 29, 2017 Cottage Plaza Multi-tenant retail 85,500 23,050 22,685 8,039 June 29, 2017 Magnolia Square Multi-tenant retail 116,000 16,000 15,692 4,866 June 29, 2017 Cinemark Seven Bridges Single-user retail 70,200 15,271 14,948 3,973 June 29, 2017 Low Country Village I & II (b) Multi-tenant retail 139,900 22,075 (67 ) 10,286 2,489,100 $ 414,765 $ 311,280 $ 156,306 (a) Aggregate proceeds are net of transaction costs and proceeds temporarily restricted related to potential 1031 Exchanges and exclude $150 of condemnation proceeds, which did not result in any additional gain recognition. (b) The following disposition proceeds are temporarily restricted related to potential 1031 Exchanges and are included in “Other assets, net” in the accompanying condensed consolidated balance sheets: Property Name Proceeds Temporarily Restricted CVS Pharmacy – Sylacauga, AL $ 3,332 Northwood Crossing 22,719 University Town Center 14,595 Edgemont Town Center 18,885 Phenix Crossing 12,324 Low Country Village I & II 21,706 $ 93,561 (c) The Company disposed of the Home Depot parcel at Century III Plaza, an existing 284,100 square foot multi-tenant retail operating property. The remaining portion of Century III Plaza is classified as held for sale as of June 30, 2017. The Company closed on the following dispositions during the six months ended June 30, 2016: Date Property Name Property Type Square Footage Consideration Aggregate Proceeds, Net (a) Gain February 1, 2016 The Gateway (b) Multi-tenant retail 623,200 $ 75,000 $ (795 ) $ 3,868 February 10, 2016 Stateline Station Multi-tenant retail 142,600 17,500 17,210 4,253 March 30, 2016 Six Property Portfolio (c) Single-user retail 230,400 35,413 12 13,618 April 20, 2016 CVS Pharmacy – Oklahoma City, OK Single-user retail 10,900 4,676 4,608 1,764 June 2, 2016 Rite Aid Store (Eckerd) – Canandaigua, NY & Tim Horton Donut Shop (d) Single-user retail 16,600 5,400 5,333 1,444 June 15, 2016 Academy Sports – Midland, TX (e) Single-user retail 61,200 5,541 17 2,220 June 23, 2016 Four Rite Aid Portfolio (f) Single-user retail 45,400 15,934 14,646 2,287 1,130,300 $ 159,464 $ 41,031 $ 29,454 (a) Aggregate proceeds are net of transaction costs and proceeds temporarily restricted related to potential 1031 Exchanges. (b) The property was disposed of through a lender-directed sale in full satisfaction of the Company’s $94,353 mortgage obligation. Immediately prior to the disposition, the lender reduced the Company’s loan obligation to $75,000 which was assumed by the buyer in connection with the disposition. Along with the loan reduction, the lender received the balance of the restricted escrows that they held and the rights to unpaid accounts receivable and forgave accrued interest, resulting in a net gain on extinguishment of debt of $13,653 . (c) Portfolio consists of the following properties: (i) Academy Sports – Houma, LA, (ii) Academy Sports – Port Arthur, TX, (iii) Academy Sports – San Antonio, TX, (iv) CVS Pharmacy – Moore, OK, (v) CVS Pharmacy – Saginaw, TX and (vi) Rite Aid Store (Eckerd) – Olean, NY. As of June 30, 2016 , disposition proceeds of $34,973 were temporarily restricted related to 1031 Exchanges and are included in “Other assets, net” in the accompanying condensed consolidated balance sheets. (d) The terms of the disposition of Rite Aid Store (Eckerd) – Canandaigua, NY and Tim Horton Donut Shop – Canandaigua, NY were negotiated as a single transaction. (e) As of June 30, 2016 , disposition proceeds of $5,383 were temporarily restricted related to a 1031 Exchange and are included in “Other assets, net” in the accompanying condensed consolidated balance sheets. (f) Portfolio consists of the following properties: (i) Rite Aid Store (Eckerd) – Cheektowaga, NY, (ii) Rite Aid Store (Eckerd), W. Main St. – Batavia, NY, (iii) Rite Aid Store (Eckerd), Union Rd. – West Seneca, NY and (iv) Rite Aid Store (Eckerd) – Greece, NY.
Schedule of assets and liabilities associated with investment properties held for sale	The following properties qualified for held for sale accounting treatment prior to or during the quarter ended June 30, 2017 . Upon meeting all applicable GAAP criteria for held for sale accounting treatment, depreciation and amortization were ceased. In addition, the assets and liabilities associated with these properties are separately classified as held for sale in the condensed consolidated balance sheet as of June 30, 2017 . Property Name Property Location Property Type Square Footage Century III Plaza, excluding the Home Depot parcel West Mifflin, Pennsylvania Multi-tenant retail 152,200 Lakepointe Towne Center Lewisville, Texas Multi-tenant retail 196,600 Irmo Station Irmo, South Carolina Multi-tenant retail 99,400 Boulevard Plaza Pawtucket, Rhode Island Multi-tenant retail 111,100 559,300 The following table presents the assets and liabilities associated with the investment properties classified as held for sale: June 30, 2017 December 31, 2016 Assets Land, building and other improvements $ 54,396 $ 45,395 Less accumulated depreciation (11,852 ) (15,769 ) Net investment properties 42,544 29,626 Other assets 1,543 1,201 Assets associated with investment properties held for sale $ 44,087 $ 30,827 Liabilities Other liabilities $ 1,142 $ 864 Liabilities associated with investment properties held for sale $ 1,142 $ 864

Equity Compensation Plans (Tabl

Equity Compensation Plans (Tables)	6 Months Ended
	Jun. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of unvested restricted shares and restricted stock units	The following table summarizes the Company’s unvested restricted shares as of and for the six months ended June 30, 2017 : Unvested Restricted Shares Weighted Average Grant Date Fair Value per Restricted Share Balance as of January 1, 2017 542 $ 15.28 Shares granted (a) 285 $ 14.60 Shares vested (271 ) $ 15.45 Balance as of June 30, 2017 (b) 556 $ 14.85 (a) Shares granted vest over periods ranging from one year to three years in accordance with the terms of applicable award agreements. (b) As of June 30, 2017 , total unrecognized compensation expense related to unvested restricted shares was $4,574 , which is expected to be amortized over a weighted average term of 1.4 years . The following table summarizes the Company’s unvested performance restricted stock units (RSUs) as of and for the six months ended June 30, 2017 : Unvested RSUs Weighted Average Grant Date Fair Value per RSU RSUs eligible for future conversion as of January 1, 2017 391 $ 14.02 RSUs granted (a) 253 $ 15.52 RSUs eligible for future conversion as of June 30, 2017 (b) 644 $ 14.61 (a) Assumptions and inputs as of the grant date included a risk-free interest rate of 1.50% , the Company’s historical common stock performance relative to the peer companies within the National Association of Real Estate Investment Trusts (NAREIT) Shopping Center Index and the Company’s common stock dividend yield of 4.32% . In 2020, following the performance period which concludes on December 31, 2019, one-third of the RSUs that are earned will convert into shares of common stock and two-thirds will convert into restricted shares with a one year vesting term. (b) As of June 30, 2017 , total unrecognized compensation expense related to unvested RSUs was $6,105 , which is expected to be amortized over a weighted average term of 2.7 years .

Mortgages Payable (Tables)

Mortgages Payable (Tables)	6 Months Ended
	Jun. 30, 2017
Debt Disclosure [Abstract]
Summary of mortgages payable	The following table summarizes the Company’s mortgages payable: June 30, 2017 December 31, 2016 Aggregate Principal Balance Weighted Average Interest Rate Weighted Average Years to Maturity Aggregate Principal Balance Weighted Average Interest Rate Weighted Average Years to Maturity Fixed rate mortgages payable (a) $ 355,389 5.22 % 4.9 $ 773,395 6.31 % 4.2 Premium, net of accumulated amortization 1,223 1,437 Discount, net of accumulated amortization (601 ) (622 ) Capitalized loan fees, net of accumulated amortization (772 ) (5,026 ) Mortgages payable, net $ 355,239 $ 769,184 (a) The fixed rate mortgages had interest rates ranging from 3.75% to 8.00% as of June 30, 2017 and December 31, 2016 . The following table summarizes the key terms of the Term Loan Due 2023: Term Loan Due 2023 Maturity Date Leverage-Based Pricing Credit Spread Ratings-Based Pricing Credit Spread $200,000 unsecured term loan 11/22/2023 1.70% – 2.55% 1.50% – 2.45%
Summary of scheduled maturities and principal amortization of indebtedness	The following table shows the scheduled maturities and principal amortization of the Company’s indebtedness as of June 30, 2017 for the remainder of 2017 , each of the next four years and thereafter and the weighted average interest rates by year. The table does not reflect the impact of any debt activity that occurred after June 30, 2017 . 2017 2018 2019 2020 2021 Thereafter Total Debt: Fixed rate debt: Mortgages payable (a) $ 27,157 $ 5,065 $ 65,352 $ 3,923 $ 22,820 $ 231,072 $ 355,389 Fixed rate term loans (b) — — — — 250,000 200,000 450,000 Unsecured notes payable (c) — — — — 100,000 600,000 700,000 Total fixed rate debt 27,157 5,065 65,352 3,923 372,820 1,031,072 1,505,389 Variable rate debt: Variable rate term loan and revolving line of credit — 200,000 — 182,000 — — 382,000 Total debt (d) $ 27,157 $ 205,065 $ 65,352 $ 185,923 $ 372,820 $ 1,031,072 $ 1,887,389 Weighted average interest rate on debt: Fixed rate debt 4.18 % 5.49 % 7.45 % 4.62 % 2.73 % 4.08 % 3.90 % Variable rate debt (e) — 2.61 % — 2.58 % — — 2.59 % Total 4.18 % 2.68 % 7.45 % 2.62 % 2.73 % 4.08 % 3.64 % (a) Excludes mortgage premium of $1,223 and discount of $(601) , net of accumulated amortization, as of June 30, 2017 . (b) $250,000 of London Interbank Offered Rate (LIBOR)-based variable rate debt has been swapped to a fixed rate through two interest rate swaps. The swaps effectively convert one-month floating rate LIBOR to a weighted average fixed rate of 0.67% through December 31, 2017. In addition, $200,000 of LIBOR-based variable rate debt has been swapped to a fixed rate through two interest rate swaps. The swaps effectively convert one-month floating rate LIBOR to a fixed rate of 1.26% through November 22, 2018. (c) Excludes discount of $(912) , net of accumulated amortization, as of June 30, 2017 . (d) The weighted average years to maturity of consolidated indebtedness was 5.3 years as of June 30, 2017 . Total debt excludes capitalized loan fees of $(7,865) , net of accumulated amortization, as of June 30, 2017 , which are included as a reduction to the respective debt balances. (e) Represents interest rates as of June 30, 2017 .

Unsecured Notes Payable (Tables

Unsecured Notes Payable (Tables)	6 Months Ended
	Jun. 30, 2017
Debt Disclosure [Abstract]
Summary of unsecured notes payable	The following table summarizes the Company’s unsecured notes payable: June 30, 2017 December 31, 2016 Unsecured Notes Payable Maturity Date Principal Balance Interest Rate/ Weighted Average Interest Rate Principal Balance Interest Rate/ Weighted Average Interest Rate Senior notes – 4.12% due 2021 June 30, 2021 $ 100,000 4.12 % $ 100,000 4.12 % Senior notes – 4.58% due 2024 June 30, 2024 150,000 4.58 % 150,000 4.58 % Senior notes – 4.00% due 2025 March 15, 2025 250,000 4.00 % 250,000 4.00 % Senior notes – 4.08% due 2026 September 30, 2026 100,000 4.08 % 100,000 4.08 % Senior notes – 4.24% due 2028 December 28, 2028 100,000 4.24 % 100,000 4.24 % 700,000 4.19 % 700,000 4.19 % Discount, net of accumulated amortization (912 ) (971 ) Capitalized loan fees, net of accumulated amortization (3,647 ) (3,886 ) Total $ 695,441 $ 695,143 The following table summarizes the Company’s term loans and revolving line of credit: June 30, 2017 December 31, 2016 Maturity Date Balance Interest Rate Balance Interest $250,000 unsecured credit facility term loan – fixed rate (a) January 5, 2021 $ 250,000 1.97 % $ 250,000 1.97 % $200,000 unsecured credit facility term loan – variable rate May 11, 2018 200,000 2.61 % 200,000 2.22 % $200,000 unsecured term loan due 2023 – fixed rate (b) November 22, 2023 200,000 2.96 % — — % Subtotal 650,000 450,000 Capitalized loan fees, net of accumulated amortization (3,446 ) (2,402 ) Term loans, net $ 646,554 $ 447,598 Revolving line of credit – variable rate (c) January 5, 2020 $ 182,000 2.58 % $ 86,000 2.12 % (a) $250,000 of LIBOR -based variable rate debt has been swapped to a weighted average fixed rate of 0.67% plus a credit spread based on a leverage grid ranging from 1.30% to 2.20% through December 31, 2017. The applicable credit spread was 1.30% as of June 30, 2017 and December 31, 2016 . (b) $200,000 of LIBOR -based variable rate debt has been swapped to a fixed rate of 1.26% plus a credit spread based on a leverage grid ranging from 1.70% to 2.55% through November 22, 2018. The applicable credit spread was 1.70% as of June 30, 2017 . (c) Excludes capitalized loan fees, which are included in “Other assets, net” in the accompanying condensed consolidated balance sheets.

Unsecured Term Loans and Revo31

Unsecured Term Loans and Revolving Line of Credit (Tables)	6 Months Ended
	Jun. 30, 2017
Line of Credit Facility [Abstract]
Summary of term loans and revolving line of credit	The following table summarizes the Company’s unsecured notes payable: June 30, 2017 December 31, 2016 Unsecured Notes Payable Maturity Date Principal Balance Interest Rate/ Weighted Average Interest Rate Principal Balance Interest Rate/ Weighted Average Interest Rate Senior notes – 4.12% due 2021 June 30, 2021 $ 100,000 4.12 % $ 100,000 4.12 % Senior notes – 4.58% due 2024 June 30, 2024 150,000 4.58 % 150,000 4.58 % Senior notes – 4.00% due 2025 March 15, 2025 250,000 4.00 % 250,000 4.00 % Senior notes – 4.08% due 2026 September 30, 2026 100,000 4.08 % 100,000 4.08 % Senior notes – 4.24% due 2028 December 28, 2028 100,000 4.24 % 100,000 4.24 % 700,000 4.19 % 700,000 4.19 % Discount, net of accumulated amortization (912 ) (971 ) Capitalized loan fees, net of accumulated amortization (3,647 ) (3,886 ) Total $ 695,441 $ 695,143 The following table summarizes the Company’s term loans and revolving line of credit: June 30, 2017 December 31, 2016 Maturity Date Balance Interest Rate Balance Interest $250,000 unsecured credit facility term loan – fixed rate (a) January 5, 2021 $ 250,000 1.97 % $ 250,000 1.97 % $200,000 unsecured credit facility term loan – variable rate May 11, 2018 200,000 2.61 % 200,000 2.22 % $200,000 unsecured term loan due 2023 – fixed rate (b) November 22, 2023 200,000 2.96 % — — % Subtotal 650,000 450,000 Capitalized loan fees, net of accumulated amortization (3,446 ) (2,402 ) Term loans, net $ 646,554 $ 447,598 Revolving line of credit – variable rate (c) January 5, 2020 $ 182,000 2.58 % $ 86,000 2.12 % (a) $250,000 of LIBOR -based variable rate debt has been swapped to a weighted average fixed rate of 0.67% plus a credit spread based on a leverage grid ranging from 1.30% to 2.20% through December 31, 2017. The applicable credit spread was 1.30% as of June 30, 2017 and December 31, 2016 . (b) $200,000 of LIBOR -based variable rate debt has been swapped to a fixed rate of 1.26% plus a credit spread based on a leverage grid ranging from 1.70% to 2.55% through November 22, 2018. The applicable credit spread was 1.70% as of June 30, 2017 . (c) Excludes capitalized loan fees, which are included in “Other assets, net” in the accompanying condensed consolidated balance sheets.
Summary of unsecured credit facility	The following table summarizes the key terms of the Unsecured Credit Facility: Leverage-Based Pricing Ratings-Based Pricing Unsecured Credit Facility Maturity Date Extension Option Extension Fee Credit Spread Unused Fee Credit Spread Facility Fee $250,000 unsecured term loan 1/5/2021 N/A N/A 1.30% - 2.20% N/A 0.90% - 1.75% N/A $200,000 unsecured term loan 5/11/2018 2 one year 0.15% 1.45% - 2.20% N/A 1.05% - 2.05% N/A $750,000 unsecured revolving line of credit 1/5/2020 2 six month 0.075% 1.35% - 2.25% 0.15% - 0.25% 0.85% - 1.55% 0.125% - 0.30%
Summary of Term Loan Due 2023	The following table summarizes the Company’s mortgages payable: June 30, 2017 December 31, 2016 Aggregate Principal Balance Weighted Average Interest Rate Weighted Average Years to Maturity Aggregate Principal Balance Weighted Average Interest Rate Weighted Average Years to Maturity Fixed rate mortgages payable (a) $ 355,389 5.22 % 4.9 $ 773,395 6.31 % 4.2 Premium, net of accumulated amortization 1,223 1,437 Discount, net of accumulated amortization (601 ) (622 ) Capitalized loan fees, net of accumulated amortization (772 ) (5,026 ) Mortgages payable, net $ 355,239 $ 769,184 (a) The fixed rate mortgages had interest rates ranging from 3.75% to 8.00% as of June 30, 2017 and December 31, 2016 . The following table summarizes the key terms of the Term Loan Due 2023: Term Loan Due 2023 Maturity Date Leverage-Based Pricing Credit Spread Ratings-Based Pricing Credit Spread $200,000 unsecured term loan 11/22/2023 1.70% – 2.55% 1.50% – 2.45%

Derivatives (Tables)

Derivatives (Tables)	6 Months Ended
	Jun. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of derivative instruments	The following table summarizes the Company’s interest rate swaps as of June 30, 2017 , which effectively convert one-month floating rate LIBOR to a fixed rate: Effective Date Notional Fixed Interest Rate Termination Date March 1, 2016 $ 100,000 0.66 % December 31, 2017 May 16, 2016 $ 150,000 0.67 % December 31, 2017 January 3, 2017 $ 100,000 1.26 % November 22, 2018 January 3, 2017 $ 100,000 1.26 % November 22, 2018
Schedule of interest rate swaps designated as cash flow hedges	The following table summarizes the Company’s interest rate swaps that were designated as cash flow hedges of interest rate risk: Number of Instruments Notional Interest Rate Derivatives June 30, 2017 December 31, 2016 June 30, 2017 December 31, 2016 Interest rate swaps 4 2 $ 450,000 $ 250,000
Schedule of estimated fair value of derivative instruments	The table below presents the estimated fair value of the Company’s derivative financial instruments, which are presented within “Other assets, net” in the condensed consolidated balance sheets. The valuation techniques utilized are described in Note 13 to the condensed consolidated financial statements. Fair Value June 30, 2017 December 31, 2016 Derivatives designated as cash flow hedges: Interest rate swaps $ 1,219 $ 743
Schedule of effect of derivative instruments on the consolidated statements of operations	The following table presents the effect of the Company’s derivative financial instruments on the accompanying condensed consolidated statements of operations and other comprehensive (loss) income: Derivatives in Cash Flow Hedging Relationships Amount of Loss (Gain) Recognized in Other Comprehensive Income on Derivative (Effective Portion) Location of (Gain) Loss Reclassified from Accumulated Other Comprehensive Income (AOCI) into Income (Effective Portion) Amount of (Gain) Loss Reclassified from AOCI into Income (Effective Portion) Location of Loss Recognized in Income on Derivative (Ineffective Portion and Amount Excluded from Effectiveness Testing) Amount of Loss Recognized in Income on Derivative (Ineffective Portion and Amount Excluded from Effectiveness Testing) Three Months Six Months Three Months Six Months Three Months Six Months 2017 $ 59 $ (413 ) Interest expense $ (86 ) $ 74 Other income, net $ 5 $ 11 2016 $ 634 $ 687 Interest expense $ 124 $ 210 Other income, net $ 3 $ 3

Earnings per Share (Tables)

Earnings per Share (Tables)	6 Months Ended
	Jun. 30, 2017
Earnings Per Share [Abstract]
Schedule of components used in the calculation of basic and diluted EPS	The following table summarizes the components used in the calculation of basic and diluted earnings per share (EPS): Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 Numerator: (Loss) income from continuing operations $ (1,865 ) $ 18,989 $ (52,129 ) $ 44,676 Gain on sales of investment properties 116,628 9,613 157,792 31,352 Preferred stock dividends (2,363 ) (2,363 ) (4,725 ) (4,725 ) Net income attributable to common shareholders 112,400 26,239 100,938 71,303 Distributions paid on unvested restricted shares (88 ) (110 ) (178 ) (240 ) Net income attributable to common shareholders excluding amounts attributable to unvested restricted shares $ 112,312 $ 26,129 $ 100,760 $ 71,063 Denominator: Denominator for earnings per common share – basic: Weighted average number of common shares outstanding 234,243 (a) 236,716 (b) 235,269 (a) 236,647 (b) Effect of dilutive securities: Stock options 1 (c) 2 (c) 1 (c) 2 (c) RSUs 574 (d) 184 (e) 572 (d) 132 (e) Denominator for earnings per common share – diluted: Weighted average number of common and common equivalent shares outstanding 234,818 236,902 235,842 236,781 (a) Excludes 556 shares of unvested restricted common stock as of June 30, 2017 , which equate to 536 and 550 shares, respectively, on a weighted average basis for the three and six months ended June 30, 2017 . These shares will continue to be excluded from the computation of basic EPS until contingencies are resolved and the shares are released. (b) Excludes 607 shares of unvested restricted common stock as of June 30, 2016 , which equate to 649 and 687 shares, respectively, on a weighted average basis for the three and six months ended June 30, 2016 . These shares were excluded from the computation of basic EPS as the contingencies remained and the shares had not been released as of the end of the reporting period. (c) There were outstanding options to purchase 41 and 53 shares of common stock as of June 30, 2017 and 2016 , respectively, at a weighted average exercise price of $19.25 and $19.39 , respectively. Of these totals, outstanding options to purchase 35 and 45 shares of common stock as of June 30, 2017 and 2016 , respectively, at a weighted average exercise price of $20.55 and $20.74 , respectively, have been excluded from the common shares used in calculating diluted EPS as including them would be anti-dilutive. (d) As of June 30, 2017 , there were 644 RSUs eligible for future conversion upon completion of the performance periods (see Note 5 to the condensed consolidated financial statements), which equate to 644 and 641 RSUs on a weighted average basis for the three and six months ended June 30, 2017 , respectively. These contingently issuable shares are included in diluted EPS based on the weighted average number of shares that would be outstanding during the period, if any, assuming June 30, 2017 was the end of the contingency periods. (e) As of June 30, 2016 , there were 391 RSUs eligible for future conversion upon completion of the performance periods, which equate to 411 and 344 RSUs on a weighted average basis for the three and six months ended June 30, 2016 , respectively. These contingently issuable shares are included in diluted EPS based on the weighted average number of shares that would have been outstanding during the period, if any, assuming June 30, 2016 was the end of the contingency periods.

Provision for Impairment of I34

Provision for Impairment of Investment Properties (Tables)	6 Months Ended
	Jun. 30, 2017
Impairment or Disposal of Tangible Assets Disclosure [Abstract]
Schedule of identified impairment indicators	As of June 30, 2017 and 2016 , the Company identified indicators of impairment at certain of its properties. Such indicators included a low occupancy rate, difficulty in leasing space and related cost of re-leasing, financially troubled tenants or reduced anticipated holding periods. The following table summarizes the results of these analyses as of June 30, 2017 and 2016 : June 30, 2017 June 30, 2016 Number of properties for which indicators of impairment were identified 7 (a) 6 (b) Less: number of properties for which an impairment charge was recorded 2 1 Less: number of properties that were held for sale as of the date the analysis was performed for which indicators of impairment were identified but no impairment charge was recorded 2 2 Remaining properties for which indicators of impairment were identified but no impairment charge was considered necessary 3 3 Weighted average percentage by which the projected undiscounted cash flows exceeded its respective carrying value for each of the remaining properties (c) 11 % 70 % (a) Includes two properties which were sold subsequent to June 30, 2017 . (b) Includes three properties which have subsequently been sold as of June 30, 2017 . (c) Based upon the estimated holding period for each asset where an undiscounted cash flow analysis was performed.
Schedule of investment property impairment charges	The Company recorded the following investment property impairment charges during the six months ended June 30, 2017 : Property Name Property Type Impairment Date Square Footage Provision for Impairment of Investment Properties Century III Plaza, excluding the Home Depot parcel (a) Multi-tenant retail June 30, 2017 152,200 $ 3,076 Lakepointe Towne Center (b) Multi-tenant retail June 30, 2017 196,600 9,958 $ 13,034 Estimated fair value of impaired properties as of impairment date $ 22,500 (a) The Company recorded an impairment charge based upon the terms and conditions of a bona fide purchase offer. This property was classified as held for sale as of June 30, 2017. The Home Depot parcel of Century III Plaza was sold on March 15, 2017. (b) The Company recorded an impairment charge based upon the terms and conditions of an executed sales contract. This property was classified as held for sale as of June 30, 2017. The Company recorded the following investment property impairment charges during the six months ended June 30, 2016 : Property Name Property Type Impairment Date Square Footage Provision for Impairment of Investment Properties South Billings Center (a) Development March 31, 2016 — $ 2,164 Mid-Hudson Center (b) Multi-tenant retail June 30, 2016 235,600 4,142 $ 6,306 Estimated fair value of impaired properties as of impairment date $ 30,500 (a) An impairment charge was recorded on March 31, 2016 based upon the terms and conditions of an executed sales contract, which was subsequently terminated. The property, which was not under active development, was sold on December 16, 2016 and additional impairment was recognized pursuant to the terms and conditions of an executed sales contract. (b) The Company recorded an impairment charge based upon the terms and conditions of an executed sales contract. This property was classified as held for sale as of June 30, 2016 and was sold on July 21, 2016.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2017
Fair Value Disclosures [Abstract]
Schedule of carrying value and estimated fair value of financial instruments	The following table presents the carrying value and estimated fair value of the Company’s financial instruments: June 30, 2017 December 31, 2016 Carrying Value Fair Value Carrying Value Fair Value Financial assets: Derivative asset $ 1,219 $ 1,219 $ 743 $ 743 Financial liabilities: Mortgages payable, net $ 355,239 $ 373,975 $ 769,184 $ 833,210 Unsecured notes payable, net $ 695,441 $ 692,274 $ 695,143 $ 679,212 Unsecured term loans, net $ 646,554 $ 650,273 $ 447,598 $ 450,421 Unsecured revolving line of credit $ 182,000 $ 182,231 $ 86,000 $ 86,130
Schedule of financial instruments measured at fair value on a recurring basis	The following table presents the Company’s financial instruments, which are measured at fair value on a recurring basis, by the level in the fair value hierarchy within which those measurements fall. Methods and assumptions used to estimate the fair value of these instruments are described after the table. Fair Value Level 1 Level 2 Level 3 Total June 30, 2017 Derivative asset $ — $ 1,219 $ — $ 1,219 December 31, 2016 Derivative asset $ — $ 743 $ — $ 743
Schedule of assets measured at fair value on a nonrecurring basis	The following table presents the Company’s assets remeasured at fair value on a nonrecurring basis as of June 30, 2017 and December 31, 2016, aggregated by the level within the fair value hierarchy in which those measurements fall. The table includes information related to properties remeasured to fair value as a result of impairment charges recorded during the six months ended June 30, 2017 and the year ended December 31, 2016, except for those properties sold prior to June 30, 2017 and December 31, 2016, respectively. Methods and assumptions used to estimate the fair value of these assets are described after the table. Fair Value Level 1 Level 2 Level 3 Total Provision for Impairment (a) June 30, 2017 Investment properties – held for sale $ — $ 22,500 (b) $ — $ 22,500 $ 13,034 December 31, 2016 Investment properties $ — $ 500 (c) $ 10,600 (d) $ 11,100 $ 13,227 (a) Excludes impairment charges recorded on investment properties sold prior to June 30, 2017 and December 31, 2016, respectively. (b) Represents the fair values of the Company’s Century III Plaza and Lakepointe Towne Center investment properties. The estimated fair value of Century III Plaza of $12,000 was based upon the expected sales price from a bona fide purchase offer and determined to be a Level 2 input. The estimated fair value of Lakepointe Towne Center of $10,500 was based upon the expected sales price from an executed sales contract and determined to be a Level 2 input. (c) Represents the fair value of the Company’s Rite Aid Store (Eckerd), Culver Rd. investment property. The estimated fair value of Rite Aid Store (Eckerd), Culver Rd. was based upon the expected sales price from a bona fide purchase offer and determined to be a Level 2 input. (d) Represents the fair values of the Company’s Crown Theater and Saucon Valley Square investment properties. The estimated fair values of Crown Theater and Saucon Valley Square of $4,000 and $6,600 , respectively, were determined using the income approach. The income approach involves discounting the estimated income stream and reversion (presumed sale) value of a property over an estimated holding period to a present value at a risk-adjusted rate. Discount rates, growth assumptions and terminal capitalization rates utilized in this approach are derived from property-specific information, market transactions and other financial and industry data. The terminal capitalization rate and discount rate are significant inputs to this valuation. The following were the key Level 3 inputs used in estimating the fair values of Crown Theater as of December 31, 2016 and Saucon Valley Square as of September 30, 2016, the date the assets were measured at fair value: 2016 Low High Rental revenue growth rates Varies (i) Varies (i) Operating expense growth rates 3.10% 18.02% Discount rates 9.35% 10.00% Terminal capitalization rates 8.35% 9.50% (i) Since cash flow models are established at the tenant level, projected rental revenue growth rates fluctuate over the course of the estimated holding period based upon the timing of lease rollover, amount of available space and other property and space-specific factors.
Schedule of financial liabilities measured at fair value for disclosure purposes	The following table presents the Company’s financial liabilities, which are measured at fair value for disclosure purposes, by the level in the fair value hierarchy within which those measurements fall. Methods and assumptions used to estimate the fair value of these instruments are described after the table. Fair Value Level 1 Level 2 Level 3 Total June 30, 2017 Mortgages payable, net $ — $ — $ 373,975 $ 373,975 Unsecured notes payable, net $ 244,308 $ — $ 447,966 $ 692,274 Unsecured term loans, net $ — $ — $ 650,273 $ 650,273 Unsecured revolving line of credit $ — $ — $ 182,231 $ 182,231 December 31, 2016 Mortgages payable, net $ — $ — $ 833,210 $ 833,210 Unsecured notes payable, net $ 234,700 $ — $ 444,512 $ 679,212 Unsecured term loans, net $ — $ — $ 450,421 $ 450,421 Unsecured revolving line of credit $ — $ — $ 86,130 $ 86,130

Organization and Basis of Pre36

Organization and Basis of Presentation (Details)	Jun. 30, 2017propertysubsidiary
Real Estate Properties [Line Items]
Number of wholly-owned subsidiaries jointly elected to be treated as a TRS | subsidiary	1
Wholly-owned | Operating properties
Real Estate Properties [Line Items]
Number of real estate properties owned	133
Wholly-owned | Operating properties | Retail
Real Estate Properties [Line Items]
Number of real estate properties owned	132
Wholly-owned | Operating properties | Office
Real Estate Properties [Line Items]
Number of real estate properties owned	1
Wholly-owned | Redevelopment properties
Real Estate Properties [Line Items]
Number of real estate properties owned	2
Investment properties held for sale | Wholly-owned | Operating properties
Real Estate Properties [Line Items]
Number of real estate properties owned	4

Acquisitions - Summary of Acqui

Acquisitions - Summary of Acquisitions (Details) $ in Thousands

May 16, 2017USD ($)ft²unit

Apr. 05, 2017USD ($)ft²

Feb. 24, 2017USD ($)ft²

Jan. 25, 2017USD ($)aft²

Jan. 13, 2017USD ($)ft²

Jun. 15, 2016USD ($)ft²

May 05, 2016USD ($)ft²

Apr. 29, 2016USD ($)ft²

Apr. 01, 2016USD ($)ft²

Mar. 29, 2016USD ($)ft²

Jan. 15, 2016USD ($)ft²property

Aug. 02, 2017USD ($)ft²

Sep. 30, 2017USD ($)

Jun. 30, 2017USD ($)ft²unit

Jun. 30, 2016USD ($)ft²

Jun. 30, 2017USD ($)ft²propertyunit

Jun. 30, 2016USD ($)ft²

Business Acquisition [Line Items]

Deferred gain

$ 2,524

$ 0

Gain on extinguishment of other liabilities

$ 0

$ 6,978

$ 0

$ 6,978

Main Street Promenade

Business Acquisition [Line Items]

Square footage | ft²

181,600

Purchase price of asset acquisition

$ 88,000

Boulevard at the Capital Centre

Business Acquisition [Line Items]

Square footage | ft²

0

Purchase price of asset acquisition

$ 2,000

Land subject to ground lease | a

70

Fee interest in land acquired | a

50

Consideration paid for fee interest in land

$ 1,939

Remaining land subject to ground lease | a

20

Term of ground lease

9 months

Amount of building and improvements derecognized

$ 11,347

Fair value of land received

15,200

Deferred gain

$ 2,524

One Loudoun Downtown - Phase II

Business Acquisition [Line Items]

Square footage | ft²

15,900

Purchase price of asset acquisition

$ 4,128

One Loudoun Downtown - Phase III

Business Acquisition [Line Items]

Square footage | ft²

9,800

Purchase price of asset acquisition

$ 2,193

One Loudoun Downtown - Phase IV

Business Acquisition [Line Items]

Square footage | ft²

0

Purchase price of asset acquisition

$ 3,500

Number of multi-family units | unit

123

2017 acquisitions

Business Acquisition [Line Items]

Square footage | ft²

207,300

207,300

Purchase price of asset acquisition

$ 99,821

Capitalized closing costs and adjustments

2,334

Mortgage debt assumed

$ 0

$ 0

One Loudoun Downtown - Phase II, Phase III and Phase IV

Business Acquisition [Line Items]

Number of properties acquired | property

3

One Loudoun Downtown

Business Acquisition [Line Items]

Number of multi-family units | unit

408

408

Shoppes at Hagerstown

Business Acquisition [Line Items]

Square footage | ft²

113,000

Acquisition price

$ 27,055

Merrifield Town Center II

Business Acquisition [Line Items]

Square footage | ft²

138,000

Acquisition price

$ 45,676

Oak Brook Promenade

Business Acquisition [Line Items]

Square footage | ft²

183,200

Acquisition price

$ 65,954

The Shoppes at Union Hill

Business Acquisition [Line Items]

Square footage | ft²

91,700

Acquisition price

$ 63,060

Mortgage debt assumed

$ 15,971

Fixed interest rate (as a percent)

3.75%

Ashland & Roosevelt - Fee Interest

Business Acquisition [Line Items]

Square footage | ft²

0

Purchase price of asset acquisition

$ 13,850

Gain on extinguishment of other liabilities

$ 6,978

Tacoma South

Business Acquisition [Line Items]

Square footage | ft²

230,700

Acquisition price

$ 39,400

Eastside

Business Acquisition [Line Items]

Square footage | ft²

67,100

Acquisition price

$ 23,842

2016 acquisitions

Business Acquisition [Line Items]

Square footage | ft²

761,700

761,700

Acquisition price

$ 278,837

Mortgage debt assumed

$ 15,316

$ 15,316

Shoppes at Hagerstown and Merrifield Town Center II

Business Acquisition [Line Items]

Number of properties acquired | property

2

Retail | Merrifield Town Center II

Business Acquisition [Line Items]

Square footage | ft²

76,000

Storage | Merrifield Town Center II

Business Acquisition [Line Items]

Square footage | ft²

62,000

Subsequent events | One Loudoun Downtown

Business Acquisition [Line Items]

Purchase price of asset acquisition

$ 25,700

Subsequent events | New Hyde Park Shopping Center

Business Acquisition [Line Items]

Square footage | ft²

32,300

Purchase price of asset acquisition

$ 22,075

Acquisitions - Acquisition Date

Acquisitions - Acquisition Date Fair Values (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Acquisition Date Fair Values
Total revenues	$ 137,339	$ 147,226	$ 281,032	$ 295,865
Net income attributable to common shareholders	112,400	26,239	100,938	71,303
2017 acquisitions
Acquisition Date Fair Values
Land	23,559		23,559
Building and other improvements, net	77,748		77,748
Acquired lease intangible assets	7,343		7,343
Acquired lease intangible liabilities	(5,477)		(5,477)
Other liabilities	(1,076)		(1,076)
Mortgages payable, net	0		0
Net assets acquired	$ 102,097		$ 102,097
Weighted average amortization period, acquired lease intangible assets			6 years
Weighted average amortization period, acquired lease intangible liabilities			13 years
2016 acquisitions
Acquisition Date Fair Values
Land		84,720		84,720
Building and other improvements, net		172,437		172,437
Acquired lease intangible assets		25,016		25,016
Acquired lease intangible liabilities		(3,991)		(3,991)
Other liabilities		0		0
Mortgages payable, net		(15,316)		(15,316)
Net assets acquired		262,866		$ 262,866
Weighted average amortization period, acquired lease intangible assets				6 years
Weighted average amortization period, acquired lease intangible liabilities				11 years
Transaction costs		$ 690		$ 690
Total revenues				21,802
Net income attributable to common shareholders				$ 5,011

Acquisitions - Condensed Pro Fo

Acquisitions - Condensed Pro Forma Financial Information (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	Apr. 29, 2016	Jun. 30, 2016	Jun. 30, 2016
Pro Forma Information [Line Items]
Total revenues		$ 147,813	$ 300,126
Net income		28,559	74,975
Net income attributable to common shareholders		$ 26,196	$ 70,250
Earnings per common share – basic and diluted
Net income per common share attributable to common shareholders		$ 0.11	$ 0.30
Weighted average number of common shares outstanding – basic		236,716	236,647
Ashland & Roosevelt - Fee Interest
Pro Forma Information [Line Items]
Purchase price of asset acquisition	$ 13,850

Acquisitions - Variable Interes

Acquisitions - Variable Interest Entities (Details) - VIE $ in Thousands	6 Months Ended
	Jun. 30, 2016USD ($)agreements	Jun. 30, 2017days	Jan. 13, 2017USD ($)
Variable Interest Entity [Line Items]
Number of days to complete tax-deferred exchange | days		180
Number of 1031 Exchange agreements | agreements	3
Main Street Promenade
Variable Interest Entity [Line Items]
Amount loaned to VIE for acquisition			$ 87,452
Oak Brook Promenade
Variable Interest Entity [Line Items]
Amount loaned to VIE for acquisition	$ 65,419
Tacoma South
Variable Interest Entity [Line Items]
Amount loaned to VIE for acquisition	39,215
Eastside
Variable Interest Entity [Line Items]
Amount loaned to VIE for acquisition	$ 23,522

Dispositions - Summary of Dispo

Dispositions - Summary of Dispositions (Details) $ in Thousands	Jun. 30, 2017USD ($)ft²	Jun. 29, 2017USD ($)ft²	Jun. 16, 2017USD ($)ft²	Jun. 06, 2017USD ($)ft²	Jun. 05, 2017USD ($)ft²	May 31, 2017USD ($)ft²	May 30, 2017USD ($)ft²	May 26, 2017USD ($)ft²	May 25, 2017USD ($)ft²	May 09, 2017USD ($)ft²	Apr. 27, 2017USD ($)ft²	Apr. 04, 2017USD ($)ft²	Mar. 24, 2017USD ($)ft²	Mar. 16, 2017USD ($)ft²	Mar. 15, 2017USD ($)ft²	Mar. 08, 2017USD ($)ft²	Mar. 07, 2017USD ($)ft²	Feb. 21, 2017USD ($)ft²	Jan. 27, 2017USD ($)ft²	Jun. 30, 2016USD ($)ft²	Jun. 23, 2016USD ($)ft²property	Jun. 15, 2016USD ($)ft²	Jun. 02, 2016USD ($)ft²	Apr. 20, 2016USD ($)ft²	Mar. 30, 2016USD ($)ft²property	Feb. 10, 2016USD ($)ft²	Feb. 01, 2016USD ($)ft²	Jun. 30, 2017USD ($)ft²	Jun. 30, 2016USD ($)ft²	Jun. 30, 2017USD ($)ft²	Jun. 30, 2016USD ($)ft²	Dec. 31, 2016USD ($)
Property Dispositions [Line Items]
Aggregate proceeds, net																														$ 312,916	$ 41,031
Gain																														157,792	31,352
Proceeds temporarily restricted related to potential 1031 Exchanges	$ 93,561																													93,561	42,905
Mortgage obligation	355,239																											$ 355,239		355,239		$ 769,184
Loan obligation assumed by the buyer																														0	15,316
Gain on extinguishment of debt																												$ 0	$ 0	$ 0	$ 13,653
Rite Aid Store (Eckerd), Culver Rd.
Property Dispositions [Line Items]
Square footage | ft²																			10,900
Consideration																			$ 500
Aggregate proceeds, net																			332
Gain																			$ 0
Shoppes at Park West
Property Dispositions [Line Items]
Square footage | ft²																		63,900
Consideration																		$ 15,383
Aggregate proceeds, net																		15,261
Gain																		$ 7,569
CVS Pharmacy - Sylacauga
Property Dispositions [Line Items]
Square footage | ft²																	10,100
Consideration																	$ 3,700
Aggregate proceeds, net																	16
Gain																	$ 1,651
Proceeds temporarily restricted related to potential 1031 Exchanges	3,332
Rite Aid Store (Eckerd) - Kill Devil Hills
Property Dispositions [Line Items]
Square footage | ft²																13,800
Consideration																$ 4,297
Aggregate proceeds, net																4,134
Gain																$ 1,857
Century III Plaza - Home Depot
Property Dispositions [Line Items]
Square footage | ft²															131,900
Consideration															$ 17,519
Aggregate proceeds, net															17,344
Gain															$ 4,487
Century III Plaza
Property Dispositions [Line Items]
Square footage | ft²															284,100
Village Shoppes at Gainesville
Property Dispositions [Line Items]
Square footage | ft²														229,500
Consideration														$ 41,750
Aggregate proceeds, net														41,380
Gain														$ 14,107
Northwood Crossing
Property Dispositions [Line Items]
Square footage | ft²													160,000
Consideration													$ 22,850
Aggregate proceeds, net													4
Gain													$ 10,007
Proceeds temporarily restricted related to potential 1031 Exchanges	22,719
University Town Center
Property Dispositions [Line Items]
Square footage | ft²												57,500
Consideration												$ 14,700
Net payment for disposition												(5)
Gain												$ 9,128
Proceeds temporarily restricted related to potential 1031 Exchanges	14,595
Edgemont Town Center
Property Dispositions [Line Items]
Square footage | ft²												77,700
Consideration												$ 19,025
Net payment for disposition												(28)
Gain												$ 8,995
Proceeds temporarily restricted related to potential 1031 Exchanges	18,885
Phenix Crossing
Property Dispositions [Line Items]
Square footage | ft²												56,600
Consideration												$ 12,400
Net payment for disposition												(28)
Gain												$ 5,699
Proceeds temporarily restricted related to potential 1031 Exchanges	12,324
Brown's Lane
Property Dispositions [Line Items]
Square footage | ft²											74,700
Consideration											$ 10,575
Aggregate proceeds, net											10,318
Gain											$ 3,408
Rite Aid Store (Eckerd) - Greer
Property Dispositions [Line Items]
Square footage | ft²										13,800
Consideration										$ 3,050
Aggregate proceeds, net										2,961
Gain										$ 830
Evans Towne Centre
Property Dispositions [Line Items]
Square footage | ft²										75,700
Consideration										$ 11,825
Aggregate proceeds, net										11,419
Gain										$ 5,226
Red Bug Village
Property Dispositions [Line Items]
Square footage | ft²									26,200
Consideration									$ 8,100
Aggregate proceeds, net									7,767
Gain									$ 2,184
Wilton Square
Property Dispositions [Line Items]
Square footage | ft²								438,100
Consideration								$ 49,300
Aggregate proceeds, net								48,503
Gain								$ 19,630
Town Square Plaza
Property Dispositions [Line Items]
Square footage | ft²							215,600
Consideration							$ 28,600
Aggregate proceeds, net							26,459
Gain							$ 3,412
Cuyahoga Falls Market Center
Property Dispositions [Line Items]
Square footage | ft²						76,400
Consideration						$ 11,500
Aggregate proceeds, net						11,101
Gain						$ 1,300
Plaza Santa Fe II
Property Dispositions [Line Items]
Square footage | ft²					224,200
Consideration					$ 35,220
Aggregate proceeds, net					33,506
Gain					$ 16,136
Rite Aid Store (Eckerd) - Columbia
Property Dispositions [Line Items]
Square footage | ft²				13,400
Consideration				$ 3,250
Aggregate proceeds, net				3,163
Gain				$ 1,046
Fox Creek Village
Property Dispositions [Line Items]
Square footage | ft²			107,500
Consideration			$ 24,825
Aggregate proceeds, net			24,415
Gain			$ 12,470
Cottage Plaza
Property Dispositions [Line Items]
Square footage | ft²		85,500
Consideration		$ 23,050
Aggregate proceeds, net		22,685
Gain		$ 8,039
Magnolia Square
Property Dispositions [Line Items]
Square footage | ft²		116,000
Consideration		$ 16,000
Aggregate proceeds, net		15,692
Gain		$ 4,866
Cinemark Seven Bridges
Property Dispositions [Line Items]
Square footage | ft²		70,200
Consideration		$ 15,271
Aggregate proceeds, net		14,948
Gain		$ 3,973
Low Country Village I & II
Property Dispositions [Line Items]
Square footage | ft²		139,900
Consideration		$ 22,075
Net payment for disposition		(67)
Gain		$ 10,286
Proceeds temporarily restricted related to potential 1031 Exchanges	$ 21,706
2017 dispositions
Property Dispositions [Line Items]
Square footage | ft²	2,489,100																											2,489,100		2,489,100
Consideration	$ 414,765																											$ 414,765		$ 414,765
Aggregate proceeds, net																														311,280
Gain																														156,306
Condemnation proceeds																														150
Maple Tree Place
Property Dispositions [Line Items]
Aggregate proceeds, net																														1,486
Gain																														$ 1,486
The Gateway
Property Dispositions [Line Items]
Square footage | ft²																											623,200
Consideration																											$ 75,000
Net payment for disposition																											(795)
Gain																											3,868
Mortgage obligation																											94,353
Loan obligation assumed by the buyer																											75,000
Gain on extinguishment of debt																											$ 13,653
Stateline Station
Property Dispositions [Line Items]
Square footage | ft²																										142,600
Consideration																										$ 17,500
Aggregate proceeds, net																										17,210
Gain																										$ 4,253
Six Property Portfolio
Property Dispositions [Line Items]
Square footage | ft²																									230,400
Consideration																									$ 35,413
Aggregate proceeds, net																									12
Gain																									$ 13,618
Proceeds temporarily restricted related to potential 1031 Exchanges																				$ 34,973
Number of properties sold | property																									6
CVS Pharmacy - Oklahoma City
Property Dispositions [Line Items]
Square footage | ft²																								10,900
Consideration																								$ 4,676
Aggregate proceeds, net																								4,608
Gain																								$ 1,764
Rite Aid Store (Eckerd) - Canandaigua & Tim Horton Donut Shop
Property Dispositions [Line Items]
Square footage | ft²																							16,600
Consideration																							$ 5,400
Aggregate proceeds, net																							5,333
Gain																							$ 1,444
Academy Sports - Midland
Property Dispositions [Line Items]
Square footage | ft²																						61,200
Consideration																						$ 5,541
Aggregate proceeds, net																						17
Gain																						$ 2,220
Proceeds temporarily restricted related to potential 1031 Exchanges																				$ 5,383
Four Rite Aid Portfolio
Property Dispositions [Line Items]
Square footage | ft²																					45,400
Consideration																					$ 15,934
Aggregate proceeds, net																					14,646
Gain																					$ 2,287
Number of properties sold | property																					4
2016 dispositions
Property Dispositions [Line Items]
Square footage | ft²																				1,130,300									1,130,300		1,130,300
Consideration																				$ 159,464									$ 159,464		$ 159,464
Aggregate proceeds, net																															41,031
Gain																															29,454
Outparcel at Beachway Plaza
Property Dispositions [Line Items]
Consideration																				2,639									$ 2,639		$ 2,639
Gain																				1,898
Proceeds temporarily restricted related to potential 1031 Exchanges																				$ 2,549

Dispositions - Assets and Liabi

Dispositions - Assets and Liabilities of Investment Properties Held for Sale (Details) $ in Thousands	Aug. 02, 2017USD ($)ft²	Jun. 30, 2017USD ($)ft²	Dec. 31, 2016USD ($)
Assets
Assets associated with investment properties held for sale		$ 44,087	$ 30,827
Liabilities
Liabilities associated with investment properties held for sale		$ 1,142	864
Investment properties held for sale
Long Lived Assets Held-for-sale [Line Items]
Square footage | ft²		559,300
Assets
Land, building and other improvements		$ 54,396	45,395
Less accumulated depreciation		(11,852)	(15,769)
Net investment properties		42,544	29,626
Other assets		1,543	1,201
Assets associated with investment properties held for sale		44,087	30,827
Liabilities
Other liabilities		1,142	864
Liabilities associated with investment properties held for sale		$ 1,142	$ 864
Century III Plaza, excluding the Home Depot parcel | Investment properties held for sale
Long Lived Assets Held-for-sale [Line Items]
Square footage | ft²		152,200
Lakepointe Towne Center | Investment properties held for sale
Long Lived Assets Held-for-sale [Line Items]
Square footage | ft²		196,600
Irmo Station | Investment properties held for sale
Long Lived Assets Held-for-sale [Line Items]
Square footage | ft²		99,400
Boulevard Plaza | Investment properties held for sale
Long Lived Assets Held-for-sale [Line Items]
Square footage | ft²		111,100
Subsequent events | Boulevard Plaza and Irmo Station
Long Lived Assets Held-for-sale [Line Items]
Consideration	$ 30,327
Subsequent events | Hickory Ridge
Long Lived Assets Held-for-sale [Line Items]
Square footage | ft²	380,600
Consideration	$ 44,020

Equity Compensation Plans (Deta

Equity Compensation Plans (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	Jun. 30, 2017	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Equity Instruments, Nonvested [Roll Forward]
Balance at the end of the period (in shares)	556	556	607	556	607
Restricted shares
Share-based Compensation Arrangement [Line Items]
Fair value of restricted shares vested				$ 3,986
Equity Instruments, Nonvested [Roll Forward]
Balance at the beginning of the period (in shares)				542
Shares/RSUs granted (in shares)				285
Shares vested (in shares)				(271)
Balance at the end of the period (in shares)	556	556		556
Equity Instruments, Nonvested, Weighted Average Grant Date Fair Value
Balance at the beginning of the period (in dollars per share)				$ 15.28
Shares/RSUs granted (in dollars per share)				14.60
Shares vested (in dollars per share)				15.45
Balance at the end of the period (in dollars per share)	$ 14.85	$ 14.85		$ 14.85
Compensation Cost Not Yet Recognized
Total unrecognized compensation expense	$ 4,574	$ 4,574		$ 4,574
RSUs
Share-based Compensation Arrangement [Line Items]
Vesting period for shares/RSUs granted				1 year
Risk-free interest rate (as a percent)				1.50%
Common stock dividend yield (as a percent)				4.32%
Conversion rate of RSUs into shares of common stock (as a percent)				33.00%
Conversion rate of RSUs into restricted shares (as a percent)				67.00%
Equity Instruments, Nonvested [Roll Forward]
Balance at the beginning of the period (in shares)				391
Shares/RSUs granted (in shares)				253
Balance at the end of the period (in shares)	644	644		644
Equity Instruments, Nonvested, Weighted Average Grant Date Fair Value
Balance at the beginning of the period (in dollars per share)				$ 14.02
Shares/RSUs granted (in dollars per share)				15.52
Balance at the end of the period (in dollars per share)	$ 14.61	$ 14.61		$ 14.61
Compensation Cost Not Yet Recognized
Total unrecognized compensation expense	$ 6,105	$ 6,105		$ 6,105
Restricted shares and RSUs
Share-based Compensation Arrangement [Line Items]
Compensation expense		$ 1,756	$ 1,676	$ 3,549	$ 3,702
Stock options
Share-based Compensation Arrangement [Line Items]
Number of options outstanding	41	41	53	41	53
Minimum | Restricted shares
Share-based Compensation Arrangement [Line Items]
Vesting period for shares/RSUs granted				1 year
Maximum | Restricted shares
Share-based Compensation Arrangement [Line Items]
Vesting period for shares/RSUs granted				3 years
Weighted average | Restricted shares
Compensation Cost Not Yet Recognized
Unrecognized compensation expense, period for recognition (in years)	1 year 5 months
Weighted average | RSUs
Compensation Cost Not Yet Recognized
Unrecognized compensation expense, period for recognition (in years)	2 years 8 months 15 days

Mortgages Payable - Summary (De

Mortgages Payable - Summary (Details) $ in Thousands	Jun. 30, 2017USD ($)property	Dec. 31, 2016USD ($)property	Jun. 30, 2017USD ($)property	Jun. 30, 2016USD ($)
Debt Instrument [Line Items]
Fixed rate mortgages payable	$ 1,887,389		$ 1,887,389
Weighted average interest rate (as a percent)	3.64%		3.64%
Premium paid in connection with defeasance of mortgages payable			$ 59,968	$ 0
Fixed rate debt
Debt Instrument [Line Items]
Fixed rate mortgages payable	$ 1,505,389		$ 1,505,389
Weighted average interest rate (as a percent)	3.90%		3.90%
Mortgages payable
Debt Instrument [Line Items]
Premium, net of accumulated amortization	$ 1,223	$ 1,437	$ 1,223
Discount, net of accumulated amortization	(601)	(622)	(601)
Capitalized loan fees, net of accumulated amortization	(772)	(5,026)	(772)
Mortgages payable, net	355,239	769,184	355,239
Amount of mortgages payable repaid or defeased			415,621
Scheduled principal payments related to amortizing loans			2,385
Mortgages payable | Fixed rate debt
Debt Instrument [Line Items]
Fixed rate mortgages payable	$ 355,389	$ 773,395	$ 355,389
Weighted average interest rate (as a percent)	5.22%	6.31%	5.22%
Weighted average years to maturity	4 years 11 months	4 years 2 months 15 days
IW JV 2009, LLC
Debt Instrument [Line Items]
Cross-collateralized mortgage balance		$ 379,435
Number of properties in cross-collateralized mortgage | property		45
Premium paid in connection with defeasance of mortgages payable			$ 60,198
Number of properties no longer securing cross-collateralized mortgage | property	45		45
Minimum | Mortgages payable
Debt Instrument [Line Items]
Fixed interest rate (as a percent)	3.75%	3.75%	3.75%
Maximum | Mortgages payable
Debt Instrument [Line Items]
Fixed interest rate (as a percent)	8.00%	8.00%	8.00%
2017 dispositions | Mortgages payable
Debt Instrument [Line Items]
Amount of mortgages payable repaid or defeased			$ 101,482
Debt repaid or defeased | Weighted average | Mortgages payable
Debt Instrument [Line Items]
Fixed interest rate (as a percent)	7.24%		7.24%

Mortgages Payable - Debt Maturi

Mortgages Payable - Debt Maturities (Details) $ in Thousands	Jun. 30, 2017USD ($)instrument	Dec. 31, 2016USD ($)
Long-term Debt, Fiscal Year Maturity
2,017	$ 27,157
2,018	205,065
2,019	65,352
2,020	185,923
2,021	372,820
Thereafter	1,031,072
Total	$ 1,887,389
Long-term Debt, Weighted Average Interest Rate
2,017	4.18%
2,018	2.68%
2,019	7.45%
2,020	2.62%
2,021	2.73%
Thereafter	4.08%
Total	3.64%
Mortgages payable
Debt Instrument [Line Items]
Premium, net of accumulated amortization	$ 1,223	$ 1,437
Discount, net of accumulated amortization	(601)	(622)
Capitalized loan fees, net of accumulated amortization	(772)	(5,026)
Unsecured notes payable
Debt Instrument [Line Items]
Discount, net of accumulated amortization	(912)	(971)
Capitalized loan fees, net of accumulated amortization	$ (3,647)	$ (3,886)
Consolidated indebtedness
Debt Instrument [Line Items]
Weighted average years to maturity	5 years 4 months
Capitalized loan fees, net of accumulated amortization	$ (7,865)
Fixed rate debt
Long-term Debt, Fiscal Year Maturity
2,017	27,157
2,018	5,065
2,019	65,352
2,020	3,923
2,021	372,820
Thereafter	1,031,072
Total	$ 1,505,389
Long-term Debt, Weighted Average Interest Rate
2,017	4.18%
2,018	5.49%
2,019	7.45%
2,020	4.62%
2,021	2.73%
Thereafter	4.08%
Total	3.90%
Fixed rate debt | Mortgages payable
Debt Instrument [Line Items]
Weighted average years to maturity	4 years 11 months	4 years 2 months 15 days
Long-term Debt, Fiscal Year Maturity
2,017	$ 27,157
2,018	5,065
2,019	65,352
2,020	3,923
2,021	22,820
Thereafter	231,072
Total	$ 355,389	$ 773,395
Long-term Debt, Weighted Average Interest Rate
Total	5.22%	6.31%
Fixed rate debt | Unsecured term loans
Long-term Debt, Fiscal Year Maturity
2,017	$ 0
2,018	0
2,019	0
2,020	0
2,021	250,000
Thereafter	200,000
Total	450,000
Fixed rate debt | Unsecured notes payable
Long-term Debt, Fiscal Year Maturity
2,017	0
2,018	0
2,019	0
2,020	0
2,021	100,000
Thereafter	600,000
Total	$ 700,000
Variable rate debt
Long-term Debt, Weighted Average Interest Rate
2,017	0.00%
2,018	2.61%
2,019	0.00%
2,020	2.58%
2,021	0.00%
Thereafter	0.00%
Total	2.59%
Variable rate debt | Variable rate term loan and revolving line of credit
Long-term Debt, Fiscal Year Maturity
2,017	$ 0
2,018	200,000
2,019	0
2,020	182,000
2,021	0
Thereafter	0
Total	382,000
$100,000 and $150,000 interest rate swaps maturing in 2017
Debt Instrument [Line Items]
Variable rate debt swapped to fixed rate	$ 250,000
Number of instruments | instrument	2
Two $100,000 interest rate swaps maturing in 2018
Debt Instrument [Line Items]
Variable rate debt swapped to fixed rate	$ 200,000
Number of instruments | instrument	2
Fixed interest rate (as a percent)	1.26%
LIBOR | $100,000 and $150,000 interest rate swaps maturing in 2017
Debt Instrument [Line Items]
Reference rate for variable interest rate	one-month floating rate LIBOR
LIBOR | Two $100,000 interest rate swaps maturing in 2018
Debt Instrument [Line Items]
Reference rate for variable interest rate	one-month floating rate LIBOR
Weighted average | $100,000 and $150,000 interest rate swaps maturing in 2017
Debt Instrument [Line Items]
Fixed interest rate (as a percent)	0.67%

Unsecured Notes Payable (Detail

Unsecured Notes Payable (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Principal balance	$ 695,441	$ 695,143
Senior Notes
Debt Instrument [Line Items]
Principal balance	700,000	700,000
Discount, net of accumulated amortization	(912)	(971)
Capitalized loan fees, net of accumulated amortization	$ (3,647)	$ (3,886)
Weighted average interest rate (as a percent)	4.19%	4.19%
Senior Notes | 4.12% Notes Due 2021
Debt Instrument [Line Items]
Principal balance	$ 100,000	$ 100,000
Stated interest rate (as a percent)	4.12%	4.12%
Senior Notes | 4.58% Notes Due 2024
Debt Instrument [Line Items]
Principal balance	$ 150,000	$ 150,000
Stated interest rate (as a percent)	4.58%	4.58%
Senior Notes | 4.00% Notes Due 2025
Debt Instrument [Line Items]
Principal balance	$ 250,000	$ 250,000
Stated interest rate (as a percent)	4.00%	4.00%
Senior Notes | 4.08% Notes Due 2026
Debt Instrument [Line Items]
Principal balance	$ 100,000	$ 100,000
Stated interest rate (as a percent)	4.08%	4.08%
Senior Notes | 4.24% Notes Due 2028
Debt Instrument [Line Items]
Principal balance	$ 100,000	$ 100,000
Stated interest rate (as a percent)	4.24%	4.24%

Unsecured Credit Facility (Deta

Unsecured Credit Facility (Details) $ in Thousands	Jun. 30, 2017USD ($)	Jan. 03, 2017USD ($)	Dec. 31, 2016USD ($)	Jan. 06, 2016USD ($)extension_options
Line of Credit Facility [Line Items]
Unsecured term loans	$ 646,554		$ 447,598
Revolving line of credit	$ 182,000		$ 86,000
$250,000 term loan
Line of Credit Facility [Line Items]
Variable interest rate spread (as a percent)	1.30%		1.30%
Unsecured term loans
Line of Credit Facility [Line Items]
Unsecured term loans	$ 650,000		$ 450,000
Capitalized loan fees, net of accumulated amortization	(3,446)		(2,402)
Term loans, net	$ 646,554		447,598
Term Loan Due 2023
Line of Credit Facility [Line Items]
Variable interest rate spread (as a percent)	1.70%
Principal amount		$ 200,000
Fixed rate debt | $250,000 term loan
Line of Credit Facility [Line Items]
Unsecured term loans	$ 250,000		$ 250,000
Interest rate (as a percent)	1.97%		1.97%
Fixed rate debt | Term Loan Due 2023
Line of Credit Facility [Line Items]
Unsecured term loans	$ 200,000		$ 0
Interest rate on term loan (as a percent)	2.96%		0.00%
Variable rate debt | $200,000 term loan
Line of Credit Facility [Line Items]
Unsecured term loans	$ 200,000		$ 200,000
Interest rate (as a percent)	2.61%		2.22%
Variable rate debt | Unsecured revolving line of credit
Line of Credit Facility [Line Items]
Revolving line of credit	$ 182,000		$ 86,000
Interest rate (as a percent)	2.58%		2.12%
$100,000 and $150,000 interest rate swaps maturing in 2017
Line of Credit Facility [Line Items]
Variable rate debt swapped to fixed rate	$ 250,000
$100,000 and $150,000 interest rate swaps maturing in 2017 | $250,000 term loan
Line of Credit Facility [Line Items]
Variable rate debt swapped to fixed rate	250,000
Two $100,000 interest rate swaps maturing in 2018
Line of Credit Facility [Line Items]
Variable rate debt swapped to fixed rate	$ 200,000
Fixed interest rate (as a percent)	1.26%
Two $100,000 interest rate swaps maturing in 2018 | Term Loan Due 2023
Line of Credit Facility [Line Items]
Variable rate debt swapped to fixed rate	$ 200,000
Fixed interest rate (as a percent)	1.26%
LIBOR | Unsecured Credit Facility
Line of Credit Facility [Line Items]
Reference rate for variable interest rate				LIBOR
LIBOR | Term Loan Due 2023
Line of Credit Facility [Line Items]
Reference rate for variable interest rate		LIBOR
LIBOR | $100,000 and $150,000 interest rate swaps maturing in 2017
Line of Credit Facility [Line Items]
Reference rate for variable interest rate	one-month floating rate LIBOR
LIBOR | $100,000 and $150,000 interest rate swaps maturing in 2017 | $250,000 term loan
Line of Credit Facility [Line Items]
Reference rate for variable interest rate	LIBOR
LIBOR | Two $100,000 interest rate swaps maturing in 2018
Line of Credit Facility [Line Items]
Reference rate for variable interest rate	one-month floating rate LIBOR
LIBOR | Two $100,000 interest rate swaps maturing in 2018 | Term Loan Due 2023
Line of Credit Facility [Line Items]
Reference rate for variable interest rate	LIBOR
Minimum | $250,000 term loan
Line of Credit Facility [Line Items]
Variable interest rate spread (as a percent)	1.30%
Minimum | Term Loan Due 2023
Line of Credit Facility [Line Items]
Variable interest rate spread (as a percent)	1.70%
Minimum | LIBOR | Term Loan Due 2023
Line of Credit Facility [Line Items]
Variable interest rate spread (as a percent)		1.70%
Maximum | $250,000 term loan
Line of Credit Facility [Line Items]
Variable interest rate spread (as a percent)	2.20%
Maximum | Term Loan Due 2023
Line of Credit Facility [Line Items]
Variable interest rate spread (as a percent)	2.55%
Maximum | LIBOR | Term Loan Due 2023
Line of Credit Facility [Line Items]
Variable interest rate spread (as a percent)		2.55%
Weighted average | $100,000 and $150,000 interest rate swaps maturing in 2017
Line of Credit Facility [Line Items]
Fixed interest rate (as a percent)	0.67%
Weighted average | $100,000 and $150,000 interest rate swaps maturing in 2017 | $250,000 term loan
Line of Credit Facility [Line Items]
Fixed interest rate (as a percent)	0.67%
KeyBank and Wells Fargo Syndicate | Unsecured Credit Facility
Line of Credit Facility [Line Items]
Aggregate borrowing capacity				$ 1,200,000
Additional borrowing capacity				400,000
Maximum borrowing capacity				1,600,000
KeyBank and Wells Fargo Syndicate | $250,000 term loan
Line of Credit Facility [Line Items]
Principal amount				250,000
KeyBank and Wells Fargo Syndicate | $200,000 term loan
Line of Credit Facility [Line Items]
Principal amount				$ 200,000
Number of extension options | extension_options				2
Term loan, period of extension of maturity (in years)				1 year
Term loan, extension fee as a percentage of amount outstanding				0.15%
KeyBank and Wells Fargo Syndicate | Unsecured revolving line of credit
Line of Credit Facility [Line Items]
Aggregate borrowing capacity				$ 750,000
Number of extension options | extension_options				2
Revolving line of credit, period of extension of maturity (in years)				6 months
Revolving line of credit, extension fee as a percentage of commitment amount				0.075%
KeyBank and Wells Fargo Syndicate | Minimum | Unsecured revolving line of credit
Line of Credit Facility [Line Items]
Quarterly unused fees (as a percent)				0.15%
KeyBank and Wells Fargo Syndicate | Minimum | LIBOR | $250,000 term loan
Line of Credit Facility [Line Items]
Variable interest rate spread (as a percent)				1.30%
KeyBank and Wells Fargo Syndicate | Minimum | LIBOR | $200,000 term loan
Line of Credit Facility [Line Items]
Variable interest rate spread (as a percent)				1.45%
KeyBank and Wells Fargo Syndicate | Minimum | LIBOR | Unsecured revolving line of credit
Line of Credit Facility [Line Items]
Variable interest rate spread (as a percent)				1.35%
KeyBank and Wells Fargo Syndicate | Maximum | Unsecured revolving line of credit
Line of Credit Facility [Line Items]
Quarterly unused fees (as a percent)				0.25%
KeyBank and Wells Fargo Syndicate | Maximum | LIBOR | $250,000 term loan
Line of Credit Facility [Line Items]
Variable interest rate spread (as a percent)				2.20%
KeyBank and Wells Fargo Syndicate | Maximum | LIBOR | $200,000 term loan
Line of Credit Facility [Line Items]
Variable interest rate spread (as a percent)				2.20%
KeyBank and Wells Fargo Syndicate | Maximum | LIBOR | Unsecured revolving line of credit
Line of Credit Facility [Line Items]
Variable interest rate spread (as a percent)				2.25%
Investment grade rated | Minimum | LIBOR | Term Loan Due 2023
Line of Credit Facility [Line Items]
Variable interest rate spread (as a percent)		1.50%
Investment grade rated | Maximum | LIBOR | Term Loan Due 2023
Line of Credit Facility [Line Items]
Variable interest rate spread (as a percent)		2.45%
Investment grade rated | KeyBank and Wells Fargo Syndicate | Minimum | Unsecured revolving line of credit
Line of Credit Facility [Line Items]
Facility fee (as a percent)				0.125%
Investment grade rated | KeyBank and Wells Fargo Syndicate | Minimum | LIBOR | $250,000 term loan
Line of Credit Facility [Line Items]
Variable interest rate spread (as a percent)				0.90%
Investment grade rated | KeyBank and Wells Fargo Syndicate | Minimum | LIBOR | $200,000 term loan
Line of Credit Facility [Line Items]
Variable interest rate spread (as a percent)				1.05%
Investment grade rated | KeyBank and Wells Fargo Syndicate | Minimum | LIBOR | Unsecured revolving line of credit
Line of Credit Facility [Line Items]
Variable interest rate spread (as a percent)				0.85%
Investment grade rated | KeyBank and Wells Fargo Syndicate | Maximum | Unsecured revolving line of credit
Line of Credit Facility [Line Items]
Facility fee (as a percent)				0.30%
Investment grade rated | KeyBank and Wells Fargo Syndicate | Maximum | LIBOR | $250,000 term loan
Line of Credit Facility [Line Items]
Variable interest rate spread (as a percent)				1.75%
Investment grade rated | KeyBank and Wells Fargo Syndicate | Maximum | LIBOR | $200,000 term loan
Line of Credit Facility [Line Items]
Variable interest rate spread (as a percent)				2.05%
Investment grade rated | KeyBank and Wells Fargo Syndicate | Maximum | LIBOR | Unsecured revolving line of credit
Line of Credit Facility [Line Items]
Variable interest rate spread (as a percent)				1.55%

Term Loan Due 2023 (Details)

Term Loan Due 2023 (Details) - Term Loan Due 2023 - USD ($) $ in Thousands	Jun. 30, 2017	Jan. 03, 2017
Debt Instrument [Line Items]
Term of debt issuance		7 years
Principal amount		$ 200,000
Variable interest rate spread (as a percent)	1.70%
Additional borrowing capacity		100,000
Maximum borrowing capacity		$ 300,000
LIBOR
Debt Instrument [Line Items]
Reference rate for variable interest rate		LIBOR
Minimum
Debt Instrument [Line Items]
Variable interest rate spread (as a percent)	1.70%
Minimum | LIBOR
Debt Instrument [Line Items]
Variable interest rate spread (as a percent)		1.70%
Maximum
Debt Instrument [Line Items]
Variable interest rate spread (as a percent)	2.55%
Maximum | LIBOR
Debt Instrument [Line Items]
Variable interest rate spread (as a percent)		2.55%
Investment grade rated | Minimum | LIBOR
Debt Instrument [Line Items]
Variable interest rate spread (as a percent)		1.50%
Investment grade rated | Maximum | LIBOR
Debt Instrument [Line Items]
Variable interest rate spread (as a percent)		2.45%

Derivatives - Schedule of Deriv

Derivatives - Schedule of Derivative Instruments (Details) - Cash flow hedges $ in Thousands	Jun. 30, 2017USD ($)instrument	Jun. 30, 2017USD ($)instrument	Jan. 03, 2017USD ($)	Dec. 31, 2016USD ($)instrument	May 16, 2016USD ($)	Mar. 01, 2016USD ($)
Interest rate swaps
Derivative [Line Items]
Number of instruments | instrument	4	4		2
Amount of gain (loss) on cash flow hedges expected to be reclassified to interest expense over the next 12 months	$ 946
Notional	$ 450,000	$ 450,000		$ 250,000
$100,000 interest rate swap maturing in 2017
Derivative [Line Items]
Notional						$ 100,000
Fixed interest rate (as a percent)						0.66%
$150,000 interest rate swap maturing in 2017
Derivative [Line Items]
Notional					$ 150,000
Fixed interest rate (as a percent)					0.67%
$100,000 interest rate swap maturing in 2018 no. 1
Derivative [Line Items]
Notional			$ 100,000
Fixed interest rate (as a percent)			1.26%
$100,000 interest rate swap maturing in 2018 no. 2
Derivative [Line Items]
Notional			$ 100,000
Fixed interest rate (as a percent)			1.26%
LIBOR
Derivative [Line Items]
Reference rate for variable interest rate		one-month floating rate LIBOR

Derivatives - Interest Rate Swa

Derivatives - Interest Rate Swaps Designated as Cash Flow Hedges (Details) - Interest rate swaps - Cash flow hedges $ in Thousands	Jun. 30, 2017USD ($)instrument	Dec. 31, 2016USD ($)instrument
Derivative [Line Items]
Number of instruments | instrument	4	2
Notional | $	$ 450,000	$ 250,000

Derivatives - Estimated Fair Va

Derivatives - Estimated Fair Value (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Interest rate swaps | Cash flow hedges
Derivatives, Fair Value [Line Items]
Fair value of derivative asset	$ 1,219	$ 743

Derivatives - Effect on Stateme

Derivatives - Effect on Statements of Operations (Details) - Interest rate swaps - Cash flow hedges - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Derivative Instruments, (Gain) Loss [Line Items]
Amount of loss (gain) recognized in other comprehensive income on derivative (effective portion)	$ 59	$ 634	$ (413)	$ 687
Amount of (gain) loss reclassified from AOCI into income (effective portion)	(86)	124	74	210
Amount of loss recognized in income on derivative (ineffective portion and amount excluded from effectiveness testing)	$ 5	$ 3	$ 11	$ 3

Equity (Details)

Equity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	1 Months Ended	3 Months Ended	6 Months Ended
	Dec. 31, 2015	Jun. 30, 2017	Jun. 30, 2017	Jun. 30, 2016
Class of Stock [Line Items]
Amount paid for shares repurchased			$ 75,697	$ 0
2015 ATM Equity Program
Class of Stock [Line Items]
Maximum aggregate offering price	$ 250,000
Aggregate offering price of remaining common shares available for sale		$ 250,000	$ 250,000
2015 Share Repurchase Program
Class of Stock [Line Items]
Maximum authorized amount for stock repurchases	$ 250,000
Number of shares repurchased		6,024	6,024
Average repurchase price per share		$ 12.55	$ 12.55
Amount paid for shares repurchased		$ 75,697	$ 75,697
Remaining authorized repurchase amount		$ 165,462	$ 165,462

Earnings per Share (Details)

Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Numerator:
(Loss) income from continuing operations			$ (1,865)	$ 18,989	$ (52,129)	$ 44,676
Gain on sales of investment properties			116,628	9,613	157,792	31,352
Preferred stock dividends			(2,363)	(2,363)	(4,725)	(4,725)
Net income attributable to common shareholders			112,400	26,239	100,938	71,303
Distributions paid on unvested restricted shares			(88)	(110)	(178)	(240)
Net income attributable to common shareholders excluding amounts attributable to unvested restricted shares			$ 112,312	$ 26,129	$ 100,760	$ 71,063
Denominator for earnings per common share – basic:
Weighted average number of common shares outstanding			234,243	236,716	235,269	236,647
Effect of dilutive securities:
Stock options			1	2	1	2
RSUs			574	184	572	132
Denominator for earnings per common share – diluted:
Weighted average number of common and common equivalent shares outstanding			234,818	236,902	235,842	236,781
Earnings Per Share, Other Disclosures
Unvested restricted common stock	556	607	556	607	556	607
Weighted average number of shares of restricted common stock			536	649	550	687
Stock options
Antidilutive Securities Excluded from Computation of Earnings per Share [Line Items]
Number of outstanding options to purchase shares of common stock	41	53	41	53	41	53
Weighted average exercise price of outstanding options (in dollars per share)	$ 19.25	$ 19.39	$ 19.25	$ 19.39	$ 19.25	$ 19.39
Number of outstanding options to purchase shares of common stock that would be anti-dilutive	35	45
Weighted average exercise price of outstanding options excluded from diluted EPS calculation (in dollars per share)	$ 20.55	$ 20.74
RSUs
Earnings Per Share, Other Disclosures
Unvested restricted common stock	644		644		644		391
Antidilutive Securities Excluded from Computation of Earnings per Share [Line Items]
Number of RSUs eligible for future conversion	644	391	644	391	644	391
Weighted average number of RSUs			644	411	641	344

Provision for Impairment of I55

Provision for Impairment of Investment Properties - Impairment Indicators (Details) - property	Jun. 30, 2017	Jun. 30, 2016
Impaired Long-Lived Assets Held and Used [Line Items]
Number of properties for which indicators of impairment were identified	7	6
Number of properties for which an impairment charge was recorded	2	1
Number of properties held for sale with impairment indicators but not impaired	2	2
Remaining properties for which indicators of impairment were identified but no impairment was considered necessary	3	3
Weighted average percentage by which projected undiscounted cash flows exceeded carrying value for each of the remaining properties	11.00%	70.00%
Number of properties with impairment indicators which were subsequently sold	2	3

Provision for Impairment of I56

Provision for Impairment of Investment Properties - Impairment Charges (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017USD ($)ft²	Jun. 30, 2016USD ($)ft²	Jun. 30, 2017USD ($)ft²	Jun. 30, 2016USD ($)ft²
Impaired Long-Lived Assets Held and Used [Line Items]
Provision for impairment of investment properties	$ 13,034	$ 4,142	$ 13,034	$ 6,306
Estimated fair value of impaired properties as of impairment date			$ 22,500	$ 30,500
Century III Plaza, excluding the Home Depot parcel
Impaired Long-Lived Assets Held and Used [Line Items]
Square footage | ft²	152,200		152,200
Provision for impairment of investment properties			$ 3,076
Lakepointe Towne Center
Impaired Long-Lived Assets Held and Used [Line Items]
Square footage | ft²	196,600		196,600
Provision for impairment of investment properties			$ 9,958
South Billings Center
Impaired Long-Lived Assets Held and Used [Line Items]
Square footage | ft²		0		0
Provision for impairment of investment properties				$ 2,164
Mid-Hudson Center
Impaired Long-Lived Assets Held and Used [Line Items]
Square footage | ft²		235,600		235,600
Provision for impairment of investment properties				$ 4,142

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Financial liabilities:
Mortgages payable, net	$ 355,239	$ 769,184
Unsecured notes payable, net	695,441	695,143
Unsecured term loans, net	646,554	447,598
Unsecured revolving line of credit	182,000	86,000
Carrying value
Financial assets:
Derivative asset	1,219	743
Financial liabilities:
Mortgages payable, net	355,239	769,184
Unsecured notes payable, net	695,441	695,143
Unsecured term loans, net	646,554	447,598
Unsecured revolving line of credit	182,000	86,000
Fair value
Financial assets:
Derivative asset	1,219	743
Financial liabilities:
Mortgages payable, net	373,975	833,210
Unsecured notes payable, net	692,274	679,212
Unsecured term loans, net	650,273	450,421
Unsecured revolving line of credit	$ 182,231	$ 86,130

Fair Value Measurements - Recur

Fair Value Measurements - Recurring Fair Value Measurements (Details) - Recurring Fair Value Measurements - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Fair Value Measurements [Line Items]
Derivative asset	$ 1,219	$ 743
Fair value, Level 2
Fair Value Measurements [Line Items]
Derivative asset	$ 1,219	$ 743

Fair Value Measurements - Nonre

Fair Value Measurements - Nonrecurring Fair Value Measurements (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Fair Value Measurements [Line Items]
Provision for impairment			$ 13,034	$ 4,142	$ 13,034	$ 6,306
Nonrecurring Fair Value Measurements
Fair Value Measurements [Line Items]
Fair value of investment properties	$ 11,100						$ 11,100
Provision for impairment							13,227
Fair value, Level 2 | Nonrecurring Fair Value Measurements
Fair Value Measurements [Line Items]
Fair value of investment properties	500						500
Fair value, Level 3 | Nonrecurring Fair Value Measurements
Fair Value Measurements [Line Items]
Fair value of investment properties	10,600						10,600
Investment properties held for sale | Nonrecurring Fair Value Measurements
Fair Value Measurements [Line Items]
Fair value of investment properties			22,500		22,500
Provision for impairment					13,034
Investment properties held for sale | Fair value, Level 2 | Nonrecurring Fair Value Measurements
Fair Value Measurements [Line Items]
Fair value of investment properties			22,500		22,500
Century III Plaza, excluding the Home Depot parcel
Fair Value Measurements [Line Items]
Fair value of investment properties			12,000		12,000
Lakepointe Towne Center
Fair Value Measurements [Line Items]
Fair value of investment properties			$ 10,500		$ 10,500
Crown Theater
Fair Value Measurements [Line Items]
Fair value of investment properties	4,000						4,000
Saucon Valley Square
Fair Value Measurements [Line Items]
Fair value of investment properties	$ 6,600						$ 6,600
Minimum | Fair value, Level 3
Fair Value Measurements [Line Items]
Operating expense growth rates		3.10%
Discount rates		9.35%
Terminal capitalization rates		8.35%
Maximum | Fair value, Level 3
Fair Value Measurements [Line Items]
Operating expense growth rates	18.02%
Discount rates	10.00%
Terminal capitalization rates	9.50%

Fair Value Measurements - Fai60

Fair Value Measurements - Fair Value Disclosures (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Fair Value Measurements [Line Items]
Mortgages payable, net	$ 355,239	$ 769,184
Unsecured notes payable, net	695,441	695,143
Unsecured term loans, net	646,554	447,598
Unsecured revolving line of credit	182,000	86,000
Fair value, Level 1
Fair Value Measurements [Line Items]
Unsecured notes payable, net	244,308	234,700
Fair value, Level 3
Fair Value Measurements [Line Items]
Mortgages payable, net	373,975	833,210
Unsecured notes payable, net	447,966	444,512
Unsecured term loans, net	650,273	450,421
Unsecured revolving line of credit	182,231	86,130
Fair value, Total
Fair Value Measurements [Line Items]
Mortgages payable, net	373,975	833,210
Unsecured notes payable, net	692,274	679,212
Unsecured term loans, net	650,273	450,421
Unsecured revolving line of credit	$ 182,231	$ 86,130
Minimum | Fair value, Level 3
Fair Value Measurements [Line Items]
Discount rate (as a percent)			9.35%
Maximum | Fair value, Level 3
Fair Value Measurements [Line Items]
Discount rate (as a percent)		10.00%
Mortgages payable | Minimum
Fair Value Measurements [Line Items]
Discount rate (as a percent)	2.90%	2.90%
Mortgages payable | Maximum
Fair Value Measurements [Line Items]
Discount rate (as a percent)	4.20%	4.60%
Unsecured notes payable
Fair Value Measurements [Line Items]
Unsecured notes payable, net	$ 700,000	$ 700,000
Unsecured term loans | Weighted average
Fair Value Measurements [Line Items]
Discount rate (as a percent)	1.42%	1.30%
Unsecured revolving line of credit
Fair Value Measurements [Line Items]
Discount rate (as a percent)	1.30%	1.30%
Notes Due 2021, 2024, 2026 and 2028 | Unsecured notes payable | Weighted average
Fair Value Measurements [Line Items]
Discount rate (as a percent)	4.35%	4.48%

Commitments and Contingencies (

Commitments and Contingencies (Details) $ in Thousands	Jun. 30, 2017USD ($)
Commitments and Contingencies [Line Items]
Amount of letters of credit outstanding	$ 13,159
Reisterstown Road Plaza
Commitments and Contingencies [Line Items]
Redevelopment costs incurred	4,857
Reisterstown Road Plaza | Minimum
Commitments and Contingencies [Line Items]
Net estimated redevelopment costs	9,500
Reisterstown Road Plaza | Maximum
Commitments and Contingencies [Line Items]
Net estimated redevelopment costs	10,500
Towson Circle
Commitments and Contingencies [Line Items]
Redevelopment costs incurred	11,207
Towson Circle | Minimum
Commitments and Contingencies [Line Items]
Net estimated redevelopment costs	33,000
Towson Circle | Maximum
Commitments and Contingencies [Line Items]
Net estimated redevelopment costs	$ 35,000

Subsequent Events (Details)

Subsequent Events (Details) $ / shares in Units, $ in Thousands	Jun. 30, 2017	Dec. 31, 2016	Aug. 02, 2017USD ($)ft²$ / shares	Jun. 30, 2017$ / shares	Jun. 30, 2016$ / shares
Subsequent Event [Line Items]
Preferred stock dividends declared (per share) | $ / shares				$ 0.875	$ 0.875
Common stock dividends declared (per share) | $ / shares				$ 0.33125	$ 0.33125
7.00% Series A cumulative redeemable preferred stock
Subsequent Event [Line Items]
Preferred stock, dividend rate	7.00%	7.00%
Subsequent events | New Hyde Park Shopping Center
Subsequent Event [Line Items]
Square footage | ft²			32,300
Gross purchase price | $			$ 22,075
Subsequent events | Boulevard Plaza
Subsequent Event [Line Items]
Square footage | ft²			111,100
Sales price | $			$ 14,300
Subsequent events | Irmo Station
Subsequent Event [Line Items]
Square footage | ft²			99,400
Sales price | $			$ 16,027
Subsequent events | Hickory Ridge
Subsequent Event [Line Items]
Square footage | ft²			380,600
Sales price | $			$ 44,020
Subsequent events | 7.00% Series A cumulative redeemable preferred stock
Subsequent Event [Line Items]
Preferred stock, dividend rate			7.00%
Preferred stock dividends declared (per share) | $ / shares			$ 0.4375
Subsequent events | Class A common stock
Subsequent Event [Line Items]
Common stock dividends declared (per share) | $ / shares			$ 0.165625