Derivative, Notional Amount of Terminated Derivatives

No definition available.

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- Definition

Derivative, Number of Instruments Terminated

+ References

No definition available.

+ Details

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- Definition

For the disposal group, amount of long-term debt before adjustment for unamortized discount or premium. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt, with initial maturities beyond one year or the normal operating cycle, if longer.

+ References

No definition available.

+ Details

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- Definition

Represents the amount of accrued interest and unused commitment fee payable as of the balance sheet date.

+ References

No definition available.

+ Details

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- Definition

Represents the period that the credit facility may be extended under certain circumstances.

+ References

No definition available.

+ Details

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- Definition

Number of extensions of a contract.

+ References

No definition available.

+ Details

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- Definition

Number of mortgage loan agreements entered into during the period.

+ References

No definition available.

+ Details

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- Definition

Payment of Derivative Fees and Accrued Interest

+ References

No definition available.

+ Details

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- Definition

Amount of accumulated amortization of debt issuance costs.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28555-108399

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-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.17)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
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-Subparagraph (SX 210.5-02(22))
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+ Details

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

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
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+ Details

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Period Type:	instant

- Definition

Amount of the fee that accompanies borrowing money under the debt instrument.

+ References

+ Details

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

- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

+ References

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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- Definition

Weighted average interest rate of debt outstanding.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	instant

- Definition

Amount, before accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

+ Details

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

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

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Period Type:	instant

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

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Period Type:	instant

- Definition

The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

Amount of cash outflow for cost from early extinguishment and prepayment of debt. Includes, but is not limited to, third-party cost, premium paid, and other fee paid to lender directly for debt extinguishment or debt prepayment. Excludes accrued interest.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3291-108585

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- Definition

The cash outflow during the period from the repayment of aggregate short-term and long-term debt. Excludes payment of capital lease obligations.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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- Definition

The cash outflow from the repayment of a long-term debt instrument issued, secured by a first mortgage deed of trust, containing a pledge of real property. The lender has the highest claim on the property in case of default.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
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- Definition

The fair value of transfer of mortgage payable in noncash investing or financing activities.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
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- Definition

Write-off of amounts previously capitalized as debt issuance cost in an extinguishment of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.8)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

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DEBT - Narrative (Details)						1 Months Ended				3 Months Ended	9 Months Ended
DEBT - Narrative (Details)	Sep. 21, 2017 USD ($)	Aug. 03, 2017 USD ($) swap	Jun. 23, 2017 USD ($)	May 30, 2017 USD ($)	Mar. 28, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2016 USD ($) agreement	May 31, 2015 USD ($)	Sep. 30, 2014 USD ($) extension_option	Sep. 30, 2017 USD ($)	Sep. 30, 2017 USD ($)	Aug. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Nov. 02, 2015 USD ($)
Debt
Deferred loan costs, gross						$ 5,533,000				$ 5,533,000	$ 5,533,000		$ 7,122,000
Deferred loan costs, accumulated amortization						1,713,000				1,713,000	1,713,000		1,818,000
Number of swaps terminated \| swap		3
Notional amount of terminated swaps		$ 65,000,000
Payment of derivative fees and accrued interest										38,000	38,000
Accrued interest and unused commitment fee payable						2,569,000				2,569,000	2,569,000		3,133,000
Unsecured credit facility entered into in September 2014
Debt
Maximum borrowing capacity									$ 850,000,000
Number of extension options \| extension_option									2
Line of credit facility extension option term									1 year
Amount available for future borrowings						21,000,000				21,000,000	21,000,000		200,000,000
Extension fee												$ 300,000
Unsecured credit facility entered into in September 2014, revolver
Debt
Maximum borrowing capacity						200,000,000			$ 450,000,000	200,000,000	200,000,000
Unsecured credit facility entered into in September 2014, revolver \| Minimum
Debt
Interest rate margin									0.20%
Unused commitment fee									0.15%
Unsecured credit facility entered into in September 2014, revolver \| Maximum
Debt
Interest rate margin									1.00%
Unused commitment fee									0.25%
Unsecured credit facility entered into in September 2014, revolver \| LIBOR \| Minimum
Debt
Interest rate margin									1.20%
Unsecured credit facility entered into in September 2014, revolver \| LIBOR \| Maximum
Debt
Interest rate margin									2.00%
Unsecured credit facility entered into in September 2014, term loan
Debt
Maximum borrowing capacity									$ 325,000,000
Unsecured credit facility entered into in September 2014, term loan \| LIBOR \| Minimum
Debt
Interest rate margin									1.15%
Unsecured credit facility entered into in September 2014, term loan \| LIBOR \| Maximum
Debt
Interest rate margin									1.95%
Unsecured credit facility entered into in September 2014, term loan \| Base rate \| Minimum
Debt
Interest rate margin									0.15%
Unsecured credit facility entered into in September 2014, term loan \| Base rate \| Maximum
Debt
Interest rate margin									0.95%
Unsecured credit facility entered into in September 2014, delayed-draw term loan
Debt
Maximum borrowing capacity									$ 75,000,000
Unused commitment fee									0.25%
Unsecured credit facilities
Debt
Gross debt						0				0	0		0
Mortgages Payable
Debt
Gross debt						$ 416,300,000				$ 416,300,000	$ 416,300,000		$ 532,437,000
Number of mortgage loan agreements entered into \| agreement							6
Amount of loan							$ 392,000,000
Unsecured Term Loan Facility Entered Into May 2015
Debt
Deferred loan costs, accumulated amortization		193,000
Maximum borrowing capacity								$ 385,000,000
Unused commitment fee								0.20%
Amount of loan														$ 385,000,000
Interest rate						2.84%				2.84%	2.84%		2.22%
Fixed interest rate						3.16%				3.16%	3.16%
Repayments of debt		65,000,000
Write off of deferred loan costs		$ 601,000
Unsecured Term Loan Facility Entered Into May 2015 \| LIBOR \| Minimum
Debt
Interest rate margin								1.60%
Unsecured Term Loan Facility Entered Into May 2015 \| LIBOR \| Maximum
Debt
Interest rate margin								2.25%
Unsecured Term Loan Facility Entered Into May 2015 \| Base rate \| Minimum
Debt
Interest rate margin								0.60%
Unsecured Term Loan Facility Entered Into May 2015 \| Base rate \| Maximum
Debt
Interest rate margin								1.25%
Unsecured term loan facility
Debt
Gross debt						$ 320,000,000				$ 320,000,000	$ 320,000,000		$ 385,000,000
Mortgage loan with a fixed interest of 6.65% per annum, due on July 15, 2018
Debt
Gross debt						0				0	0		$ 26,136,000
Fixed interest rate													6.65%
Mortgage loan with a fixed interest of 4.14% per annum, due on July 1, 2026
Debt
Gross debt						$ 370,300,000				$ 370,300,000	$ 370,300,000		$ 392,000,000
Fixed interest rate						4.14%				4.14%	4.14%
Mortgage loan with a fixed interest of 5.18% per annum, due on June 5, 2021
Debt
Gross debt						$ 0				$ 0	$ 0		$ 29,167,000
Fixed interest rate													5.18%
Disposal Group, Held-for-sale, Not Discontinued Operations \| Mortgage loan with a fixed interest of 4.14% per annum, due on July 1, 2026
Debt
Mortgage assumed by buyer						$ 21,700,000
Disposal Group, Held-for-sale, Not Discontinued Operations \| Mortgage loan with a fixed interest of 5.18% per annum, due on June 5, 2021
Debt
Fixed interest rate						5.18%				5.18%	5.18%
211 Main Street, San Francisco \| Disposal Group, Disposed of by Sale, Not Discontinued Operations
Debt
Payment of mortgages payable					$ 25,331,000
Mortgage prepayment penalty					$ 1,508,000
3636 McKinney Avenue and 3839 McKinney Avenue, Dallas, Texas \| Disposal Group, Disposed of by Sale, Not Discontinued Operations
Debt
Payment of mortgages payable				$ 15,448,000
Mortgage prepayment penalty				$ 1,901,000
4649 Cole Avenue, Dallas, Texas \| Disposal Group, Disposed of by Sale, Not Discontinued Operations
Debt
Payment of mortgages payable			$ 23,333,000
Mortgage prepayment penalty			$ 2,812,000
7083 Hollywood Boulevard \| Disposal Group, Held-for-sale, Not Discontinued Operations
Debt
Mortgage assumed by buyer	$ 21,700,000
4200 Scotland Street, Houston, TX
Debt
Gross debt						$ 28,715,000				$ 28,715,000	$ 28,715,000
4200 Scotland Street, Houston, TX \| Disposal Group, Held-for-sale, Not Discontinued Operations
Debt
Debt, gross						$ 28,715,000				$ 28,715,000	$ 28,715,000