Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2013

Fair Value Disclosures [Abstract]

Fair Value, by Balance Sheet Grouping [Table Text Block]

All financial instruments of the Company are reflected in the accompanying Consolidated Balance Sheets at amounts which, in management's estimation, reasonably approximate their fair values, except for the following as of September 30, 2013 and December 31, 2012 (in thousands):

		2013			2012
		Carrying Amount	Fair Value		Carrying Amount	Fair Value
Financial assets:
Notes receivable	$	26,128	25,755	$	23,751	23,677
Financial liabilities:
Notes payable	$	1,764,437	1,930,004	$	1,771,891	2,000,000
Unsecured credit facilities	$	100,000	100,476	$	170,000	170,200

Fair Value, Assets Measured on Recurring Basis [Table Text Block]

he following table presents the placement in the fair value hierarchy of assets and liabilities that are measured at fair value on a recurring basis as of September 30, 2013 and December 31, 2012 (in thousands):

		Fair Value Measurements as of September 30, 2013
				Quoted Prices in Active Markets for Identical Assets	Significant Other Observable Inputs		Significant Unobservable Inputs
Assets		Balance		(Level 1)	(Level 2)		(Level 3)
Trading securities held in trust	$	25,421		25,421	—		—
Interest rate derivatives		26,540		—	26,540		—
Total	$	51,961		25,421	26,540		—
Liabilities
Interest rate derivatives	$	(45	)	—	(45	)	—

		Fair Value Measurements as of December 31, 2012
				Quoted Prices in Active Markets for Identical Assets	Significant Other Observable Inputs		Significant Unobservable Inputs
Assets		Balance		(Level 1)	(Level 2)		(Level 3)
Trading securities held in trust	$	23,429		23,429	—		—
Interest rate derivatives		4,307		—	4,307		—
Total	$	27,736		23,429	4,307		—
Liabilities
Interest rate derivatives	$	(76	)	—	(76	)	—

Fair Value, Assets and Liabilities Measured on Nonrecurring Basis [Table Text Block]

The following table presents fair value measurements that were measured at fair value on a nonrecurring basis as of September 30, 2013 and December 31, 2012 (in thousands):

		Fair Value Measurements as of September 30, 2013
			Quoted Prices in Active Markets for Identical Assets	Significant Other Observable Inputs	Significant Unobservable Inputs	Total Gains (Losses)
Assets		Balance	(Level 1)	(Level 2)	(Level 3)
Long-lived assets held and used
Operating and development properties	$	4,686	—	—	4,686	(6,000	)

		Fair Value Measurements as of December 31, 2012
			Quoted Prices in Active Markets for Identical Assets	Significant Other Observable Inputs	Significant Unobservable Inputs	Total Gains (Losses) (1)
Assets		Balance	(Level 1)	(Level 2)	(Level 3)
Long-lived assets held and used
Operating and development properties	$	49,673	—	—	49,673	(54,500	)

⁽¹⁾ Excludes impairments for properties sold during the year ended December 31, 2012.

Ranges Of Key Inputs Used In Determining The Fair Value Of Real Estate [Table Text Block]

The following are the key inputs used in determining the fair value of real estate measured using Level 3 inputs as of September 30, 2013 and December 31, 2012:

	2013		2012
			Low		High
Direct cap rates	8.0	%	8.3	%	8.5	%
Rental growth rates	0.0	%	(8.3	)%	2.5	%
Discount rates	9.0	%	10.5	%	10.5	%
Terminal cap rates	8.5	%	8.8	%	8.8	%