Notes Payable (Credit Facility) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2015 property
Credit Facility
Maximum borrowings available under credit facility	$ 475.0
Line of Credit Facility, Revolving loan extension period	1 year
Maximum increased amount of revolving loans	225.0
Line of Credit Facility, Number of real estate properties held as collateral	10
Available borrowings	180.3
LIBOR interest index Period One	1 month
LIBOR interest index Period Two	3 months
LIBOR Interest Index Period Three	6 months
Line of Credit Facility, Interest Rate During Period	3.10%
Credit facility \| Federal Funds Effective Rate
Credit Facility
Applicable margin (as a percent)	0.50%
Credit facility \| Debt Instrument Variable Rate Base Libor [Member]
Credit Facility
Applicable margin (as a percent)	1.00%
Revolving Credit Facility [Member]
Credit Facility
Maximum borrowings available under credit facility	225.0
Line of Credit Facility, Fair Value of Amount Outstanding	96.0
Term Loan Facility [Member]
Credit Facility
Maximum borrowings available under credit facility	250.0
Line of Credit Facility, Fair Value of Amount Outstanding	$ 125.0
Minimum [Member]
Credit Facility
Line of Credit, applicable margin	0.45%
Maximum [Member]
Credit Facility
Line of Credit, applicable margin	2.30%

LIBOR interest index Period One

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- Definition

LIBOR Interest Index Period Three

+ References

No definition available.

+ Details

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- Definition

LIBOR interest index Period Two

+ References

No definition available.

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- Definition

Line of Credit, applicable margin

+ References

No definition available.

+ Details

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- Definition

Represents the amount of maximum increase to borrowing capacity under the credit facility that may be achieved upon lender approval and payment of certain activation fees to the agent and lenders.

+ References

No definition available.

+ Details

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- Definition

Line of Credit Facility, Number of real estate properties held as collateral

+ References

No definition available.

+ Details

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- Definition

Line of Credit Facility, Revolving loan extension period

+ References

No definition available.

+ Details

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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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- Definition

Fair value of the amount outstanding under the credit facility.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 10

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=35750535&loc=d3e13433-108611

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 12

-URI http://asc.fasb.org/extlink&oid=35750535&loc=d3e13476-108611

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- Definition

The effective interest rate during the reporting period.

+ 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

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- 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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- 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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