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Noncontrolling Interests Redeemable interest in property partnership (Narrative) (Details) - USD ($) $ in Thousands				9 Months Ended
	Sep. 15, 2015	Aug. 06, 2015	Oct. 04, 2012	Sep. 30, 2016	Sep. 30, 2015
Noncontrolling Interest [Line Items]
Payments for Repurchase of Redeemable Noncontrolling Interest				$ 0	$ 108,499
Fountain Square [Member]
Noncontrolling Interest [Line Items]
Aggregate purchase price			$ 385,000
Indebtedness assumed			$ 211,300
Ownership Percentage	50.00%	50.00%	50.00%
Fixed Price to Acquire Remaining Portion of Joint venture		$ 100,900
Payments to Acquire Businesses, Gross			$ 87,000
Ownership Percentage by the Company			50.00%
Future Fixed Price to Acquire Remaining Portion of Joint venture			$ 102,000
Fixed Price Option Expiration Date			Jan. 31, 2016
Payments for Repurchase of Redeemable Noncontrolling Interest	$ 100,900
Mortgage debt assumed upon acquisition of noncontrolling interest	$ 105,600

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Amount of long-term debt due after one year or the normal operating cycle, if longer, assumed at the acquisition date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=56956791&loc=d3e4845-128472

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The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

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The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Investing Activities
-URI http://asc.fasb.org/extlink&oid=6516133

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3213-108585

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