Debt (Tables)

3 Months Ended

Mar. 31, 2014

Debt Disclosure [Abstract]

Schedule of Debt [Table Text Block]

		Interest Rate at			Balance at
(Amounts in thousands)		March 31, 2014			March 31, 2014		December 31, 2013
Mortgages Payable:
	Fixed rate		4.56%	$	7,546,030	$	7,563,133
	Variable rate		2.55%		1,367,328		768,860
			4.25%	$	8,913,358	$	8,331,993
Unsecured Debt:
	Senior unsecured notes		5.67%	$	1,343,442	$	1,350,855
	Revolving credit facility debt		1.31%		88,138		295,870
			5.41%	$	1,431,580	$	1,646,725