ACQUISITION AND DISPOSITION OF PROPERTIES, DISCONTINUED OPERATIONS AND PROPERTIES HELD FOR SALE Held For Sale (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014 property	Dec. 31, 2013
Discontinued Operations and Disposal Groups [Abstract]
Number of properties held-for-sale	2akr_NumberofPropertiesHeldforSale
Assets of discontinued operations and properties held for sale	$ 56,073	$ 20,434
Liabilities of discontinued operations and properties held for sale	$ 25,500	$ 2,507

Amount classified as liabilities attributable to disposal group held for sale or disposed of.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 20

-Section 45

-Paragraph 10

-URI http://asc.fasb.org/extlink&oid=6892542&loc=d3e1107-107759

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 20

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6360339&loc=d3e1436-107760

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant