Represents the fixed charge coverage ratio required by the financial covenant under the terms of the debt agreement.

No definition available.

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- Definition

Represents the percentage of net proceeds from equity issuances added to the minimum tangible net worth in calculating the financial covenant per the terms of the debt agreement.

+ References

No definition available.

+ Details

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- Definition

Represents the minimum tangible net worth required by the financial covenant under the terms of the debt agreement.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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- Definition

Represents the total indebtedness to total asset value coverage ratio required by the financial covenant under the terms of the debt agreement.

+ References

No definition available.

+ Details

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- Definition

Represents the percentage of funds from operations that can be distributed on common shares as a condition under the covenant.

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
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Period Type:	duration

- Definition

Represents the floor for the variable rate base of the debt instrument.

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
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Period Type:	duration

- 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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- Definition

The reference rate for the variable rate of the debt instrument, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR.

+ References

No definition available.

+ Details

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

Name:	us-gaap_DebtInstrumentLineItems
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- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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Data Type:	xbrli:durationItemType
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Period Type:	duration

- Definition

Weighted average interest rate of debt outstanding.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtWeightedAverageInterestRate
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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

For an unclassified balance sheet, the amount as of the balance sheet date of capitalized costs associated with the issuance of debt instruments (for example, legal, accounting, underwriting, printing, and registration costs) that will be charged against earnings over the life of the debt instruments to which such costs pertain. Such amount is before the consideration of accumulated amortization.

+ 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=6451184&loc=d3e28555-108399

+ Details

Name:	us-gaap_DeferredFinanceCostsGross
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The reference rate for the variable rate of the interest rate derivative, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeDescriptionOfVariableRateBasis
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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Gross amount of debt extinguished.

+ References

No definition available.

+ Details

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

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

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

- Definition

The fee, expressed as a percentage of the line of credit facility, for the line of credit facility regardless of whether the facility has been used.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- 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

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19(b),22(b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

+ Details

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

- Definition

Including the current and noncurrent portions, carrying value as of the balance sheet date of uncollateralized debt obligations (with maturities initially due after one year or beyond the operating cycle if longer).

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.16)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 16

-Article 9

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.16)

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Article 5

-Subsection 19, 20, 22

+ Details

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

- 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=26872669&loc=d3e20235-122688

+ Details

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

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REVOLVING CREDIT FACILITY AND UNSECURED TERM LOANS (Details) (USD $)	12 Months Ended	0 Months Ended			12 Months Ended	0 Months Ended
	Dec. 31, 2013	Jun. 18, 2013	Aug. 05, 2014	Jun. 20, 2011	Dec. 31, 2014	Dec. 17, 2013	Dec. 09, 2011
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Loan procurement costs capitalized	$ 17,300,000us-gaap_DeferredFinanceCostsGross				17,000,000us-gaap_DeferredFinanceCostsGross
Loan procurement amortization expense - early repayment of debt	414,000
Unsecured term loan borrowings outstanding	400,000,000us-gaap_UnsecuredDebt				400,000,000us-gaap_UnsecuredDebt
Term Loan A
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Maximum borrowing capacity		100,000,000
Term Loan B
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Maximum borrowing capacity		100,000,000
Term Loan Facility, Prior to Amendment \| Term Loan A \| Baa3/BBB
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Interest rate, basis spread (as a percent)		1.85%
Term Loan Facility, Prior to Amendment \| Term Loan A \| Baa2/BBB
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Interest rate, basis spread (as a percent)		1.65%
Term Loan Facility, Prior to Amendment \| Term Loan B \| Baa3/BBB
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Interest rate, basis spread (as a percent)		2.00%
Term Loan Facility, Prior to Amendment \| Term Loan B \| Baa2/BBB
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Interest rate, basis spread (as a percent)		1.80%
Term Loan Facility, As Amended \| Term Loan A \| Baa3/BBB
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Interest rate, basis spread (as a percent)			1.50%
Term Loan Facility, As Amended \| Term Loan B \| Baa3/BBB
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Interest rate, basis spread (as a percent)			1.40%
Term Loan Facility
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Loan procurement costs capitalized		2,100,000	200,000
Effective weighted average interest rate (as a percent)	3.22%
Net proceeds from equity issuances added to minimum tangible net worth (as a percent)	75.00%
Term Loan Facility \| Interest rate swap
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Derivative, variable interest rate base	Thirty day LIBOR
Term Loan Facility \| Minimum
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Fixed charge coverage ratio	1.5
Tangible net worth	821,211,200
Term Loan Facility \| Maximum
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Total indebtedness to total asset value ratio (as a percent)	60.00%
Percentage of funds from operations that can be distributed on common shares	95.00%
Term Loan Facility \| Term Loan A
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Maximum borrowing capacity				100,000,000
Term of debt instrument				5 years
Term Loan Facility \| Term Loan A \| Baa3/BBB
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Interest rate, basis spread (as a percent)					1.30%
Variable interest rate basis					LIBOR
Variable interest rate floor (as a percent)					0.00%
Term Loan Facility \| Term Loan B
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Maximum borrowing capacity				100,000,000
Term of debt instrument				7 years
Term Loan Facility \| Term Loan B \| Baa3/BBB
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Interest rate, basis spread (as a percent)					1.15%
Variable interest rate basis					LIBOR
Variable interest rate floor (as a percent)					0.00%
Term Loan Facility \| Term Loan C
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Loan procurement amortization expense - early repayment of debt	400,000
Term Loan Facility \| Unsecured term loan
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Unsecured term loan borrowings outstanding	200,000,000
Credit Facility, Prior to Amendment \| Revolver \| Baa3/BBB
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Interest rate, basis spread (as a percent)		1.80%
Credit Facility, Prior to Amendment \| Revolver \| Baa2/BBB
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Interest rate, basis spread (as a percent)		1.50%
Credit Facility, Prior to Amendment \| Term Loan C \| Baa3/BBB
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Interest rate, basis spread (as a percent)		1.75%
Credit Facility, Prior to Amendment \| Term Loan C \| Baa2/BBB
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Interest rate, basis spread (as a percent)		1.45%
Credit Facility, Prior to Amendment \| Term Loan D \| Baa3/BBB
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Interest rate, basis spread (as a percent)		1.75%
Credit Facility, Prior to Amendment \| Term Loan D \| Baa2/BBB
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Interest rate, basis spread (as a percent)		1.45%
Credit Facility, As Amended \| Revolver \| Baa3/BBB
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Interest rate, basis spread (as a percent)			1.60%
Credit Facility, As Amended \| Revolver \| Baa2/BBB
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Interest rate, basis spread (as a percent)			1.30%
Credit Facility, As Amended \| Term Loan C \| Baa3/BBB
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Interest rate, basis spread (as a percent)			1.50%
Credit Facility, As Amended \| Term Loan C \| Baa2/BBB
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Interest rate, basis spread (as a percent)			1.30%
Credit Facility, As Amended \| Term Loan D \| Baa3/BBB
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Interest rate, basis spread (as a percent)			1.50%
Credit Facility, As Amended \| Term Loan D \| Baa2/BBB
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Interest rate, basis spread (as a percent)			1.30%
Credit Facility
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Remaining borrowing capacity	261,200,000
Effective weighted average interest rate (as a percent)					2.95%
Net proceeds from equity issuances added to minimum tangible net worth (as a percent)	75.00%
Credit Facility \| Minimum
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Fixed charge coverage ratio	1.5
Tangible net worth	821,211,200
Credit Facility \| Maximum
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Total indebtedness to total asset value ratio (as a percent)	60.00%
Percentage of funds from operations that can be distributed on common shares	95.00%
Credit Facility \| Revolver
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Maximum borrowing capacity		300,000,000					300,000,000
Outstanding letter of credit	30,000,000
Credit Facility \| Revolver \| Baa3/BBB
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Interest rate, basis spread (as a percent)					1.30%
Variable interest rate basis					LIBOR
Variable interest rate floor (as a percent)					0.00%
Facility fee (as a percent)					0.20%
Credit Facility \| Term Loan C
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Maximum borrowing capacity		100,000,000					100,000,000
Repayment of outstanding debt						100,000,000
Credit Facility \| Term Loan C \| Baa3/BBB
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Interest rate, basis spread (as a percent)					1.30%
Variable interest rate basis					LIBOR
Variable interest rate floor (as a percent)					0.00%
Credit Facility \| Term Loan D
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Maximum borrowing capacity		200,000,000					200,000,000
Credit Facility \| Term Loan D \| Baa3/BBB
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Interest rate, basis spread (as a percent)					1.30%
Variable interest rate basis					LIBOR
Variable interest rate floor (as a percent)					0.00%
Credit Facility \| Unsecured term loan
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Unsecured term loan borrowings outstanding	200,000,000
Credit Facility \| Unsecured revolving credit facility
SECURED CREDIT FACILITY, UNSECURED CREDIT FACILITY AND SECURED TERM LOANS
Unsecured term loan borrowings outstanding					78,000,000
Remaining borrowing capacity					222,000,000