Acquisitions, Dispositions and Held for Sale (Details) $ in Thousands		1 Months Ended										3 Months Ended						6 Months Ended	9 Months Ended		12 Months Ended
		Sep. 30, 2016 USD ($)	Jul. 31, 2016 USD ($)	May 31, 2016 USD ($)	Apr. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Nov. 30, 2015 USD ($)	Jul. 31, 2015 USD ($)	Jun. 30, 2015 USD ($)	Apr. 30, 2015 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2016 USD ($) outparcel	Sep. 30, 2015 USD ($)	Dec. 31, 2015 USD ($)	Jun. 18, 2015 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales Price, Gross																			$ 153,960		$ 104,860
Sales Price, Net																			149,972		103,537
Gain																			3,728		21,331
Loss on impairment												$ 53,558				$ 884			$ 116,736	$ 3,665
Percentage of equity interest in real estate property		50.00%										50.00%							50.00%
Gain (loss) on sale of real estate																			$ 14,503	$ 18,167
Held for sale	[1]	$ 32,250					$ 0					$ 32,250			$ 0			$ 0	$ 32,250		$ 0
Real estate held for sale as percentage of total assets		0.50%										0.50%							0.50%
River Ridge Mall
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percentage of equity interest in real estate property		25.00%										25.00%							25.00%
Oak Branch Business Center
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales Price, Gross		$ 2,400
Sales Price, Net		2,148
Gain		0
Loss on impairment		$ 122
The Lakes Mall/Fashion Square
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales Price, Gross			$ 66,500
Sales Price, Net			65,514
Gain			273
Loss on impairment													$ 32,096
Bonita Lakes Mall and Crossing
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales Price, Gross				$ 27,910
Sales Price, Net				27,614
Gain				$ 216
Loss on impairment														$ 5,323
The Crossings at Marshalls Creek
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales Price, Gross					$ 23,650
Sales Price, Net					21,791
Gain					$ 3,239
River Ridge Mall
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales Price, Gross						$ 33,500
Sales Price, Net						32,905
Gain						$ 0
Loss on impairment														$ 9,510
Ownership percentage sold						75.00%													75.00%
Mayfaire Community Center
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales Price, Gross							56,300
Sales Price, Net							55,955
Gain							0
Loss on impairment															397
Chapel Hill Crossing
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales Price, Gross							2,300
Sales Price, Net							2,178
Gain							$ 0
Loss on impairment															1,914
Waynesville Commons
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales Price, Gross								$ 14,500
Sales Price, Net								14,289
Gain								$ 5,071
Madison Plaza
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales Price, Gross									$ 5,700
Sales Price, Net									5,472
Gain									$ 2,769
Eastgate Crossing
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales Price, Gross										$ 21,060
Sales Price, Net										20,688
Gain										13,491
Proceeds from lease of tenant space													478		574
Earn out proceeds, amount earned													$ 508		$ 625
Mortgage loan assumed at sale										$ 14,570
Madison Square
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales Price, Gross											$ 5,000
Sales Price, Net											4,955
Gain											$ 0
Loss on impairment																	$ 2,620
Mayfaire Community Center
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Business combination, ownership percentage																						100.00%
Sales price																						$ 191,988
Revenue from acquiree included in consolidated financial statements																		8,982
Income from acquiree included in consolidated financial statements																		$ 410
Mortgages | Fashion Square
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Mortgage note payables assumed			$ 38,237
Outparcel Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain (loss) on sale of real estate																			$ 8,113
Number of properties disposed of | outparcel																			8
Parking Deck Project
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain (loss) on sale of real estate																			$ 2,184

[1] As of September 30, 2016, includes $618,034 of assets related to consolidated variable interest entities that can be used only to settle obligations of the consolidated variable interest entities and $484,231 of liabilities of consolidated variable interest entities for which creditors do not have recourse to the general credit of the Company. See Note 5.