Indebtedness (Tables)

9 Months Ended

Sep. 30, 2011

Debt Disclosure [Abstract]

Fair Value, Liabilities Measured on a Recurring Basis, Disclosure Only

	Book Value at 12/31/10		Book Value at 9/30/11		Fair Value at 12/31/10		Issuances and Assumptions		Payoffs			Adjustments to Fair Value			Fair Value at 9/30/11
Fixed rate secured debt	$	1,042,722	$	1,162,147	$	1,069,562	$	143,732	$	(24,056	)	$	75,065		$	1,264,303
Variable rate secured debt	22,906		22,121		22,906		—		(785		)	—			22,121
Unsecured notes	2,948,405		2,783,762		3,164,651		—		(166,345		)	(63,773		)	2,934,533
Unsecured lines of credit	193,046		304,293		193,224		111,248		—			4,815			309,287
Total	$	4,207,079	$	4,272,323	$	4,450,343	$	254,980	$	(191,186	)	$	16,107		$	4,530,244

Unsecured Lines of Credit

Description	Maximum Capacity		Maturity Date	Outstanding Balance at September 30, 2011
Unsecured Line of Credit - DRLP	$	850,000	February 2013	$	284,000
Unsecured Line of Credit - Consolidated Subsidiary	$	30,000	July 2012	$	20,293