NET INCOME PER COMMON SHARE (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended	6 Months Ended
Jun. 30, 2013	Jun. 30, 2013	Jun. 30, 2013 Operating Partnership Notes	Jun. 21, 2013 Operating Partnership Notes
Net income per common share
Principal amount of notes			$ 250,000
Interest rate (as a percent)			2.375%	2.375%
Exchange price (in dollars per share)			$ 55.69
Shares related to the notes included in the computation for diluted earnings per share	0	0
Exchangeable preferred operating partnership units settled in cash, minimum	$ 115,000	$ 115,000

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Represents the minimum amount of equity component of convertible preferred operating partnership units which will be settled in cash upon conversion.

+ References

No definition available.

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- Definition

The price per share of the conversion feature embedded in the debt instrument.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 470

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-Section 50

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- Definition

The stated principal amount of the debt instrument at time of issuance, which may vary from the carrying amount because of unamortized premium or discount.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

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-Publisher AICPA

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-Number 21

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- Definition

Interest rate stated in the contractual debt agreement.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

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- Definition

Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of convertible debt securities using the if-converted method.

+ References

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-Publisher FASB

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-Name Statement of Financial Accounting Standard (FAS)

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