Amount of assets held-for-sale that are not part of a disposal group.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 15
-Paragraph 4
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=77912953&loc=d3e400-110220

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This element represents the amount of gain (loss) on sale of properties during the reporting period net of the applicable income taxes realized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 974
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-15.(a)(1)(ii))
-URI http://asc.fasb.org/extlink&oid=6875705&loc=d3e641549-123027

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Period Type:	duration

- References

No definition available.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
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- Definition

Amount of loss contingency liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14326-108349

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Balance Type:	credit
Period Type:	instant

- Definition

Amount charged against operating income increasing loss contingency liability, after adjustments to reduce previously estimated charges.

+ References

+ Details

Name:	us-gaap_LossContingencyAccrualProvision
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The cash inflow from the sale of formerly productive land held for sale, anything permanently fixed to it, including buildings, structures on it, and so forth.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3179-108585

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Dispositions of Properties (Details) - USD ($) $ in Thousands			3 Months Ended		6 Months Ended
	Oct. 20, 2017	Jan. 06, 2017	Sep. 30, 2017	Jun. 30, 2017	Jun. 30, 2017
Gain (loss) on sale of property
Gain (loss) on sale of property				$ (20,492)	$ (18,203)
Disposal Group, Held-for-sale or Disposed of by Sale, Not Discontinued Operations \| Office Property in Baltimore Maryland
Gain (loss) on sale of property
Assets Held-for-sale, Not Part of Disposal Group			$ 31,600	31,900	31,900
Loss contingency on property held			20,700	$ 20,500	$ 20,500
Provision for loss on property held			$ 300
Disposal group disposed of by sale, not classified as discontinued operations \| Office Property in Baltimore Maryland
Gain (loss) on sale of property
Gain (loss) on sale of property	$ 20,800
Net Proceeds	$ 31,600
Office Property In Milpitas, California \| Disposal group disposed of by sale, not classified as discontinued operations
Gain (loss) on sale of property
Gain (loss) on sale of property		$ 2,300