Risk Management and Use of Financial Instruments Risk Management and Use of Financial Instruments (Tables)

3 Months Ended

Mar. 31, 2013

Derivatives, Fair Value [Line Items]

Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block]

Hedge Product	Hedge Type	Designation		Notional Amount				Strike		Trade Date	Maturity Date	Fair value
				03/31/2013		12/31/2012						03/31/2013		12/31/2012
Swap	Interest Rate	Cash Flow	(a)	$	200,000	$	200,000	3.623	%	December 6-13, 2011	February 1, 2019	$	7,761	$	8,859
Swap	Interest Rate	Cash Flow	(a)	77,000		77,000		2.703	%	December 9-13, 2011	February 1, 2016	1,229		1,343
Swap	Interest Rate	Cash Flow	(a)	50,000		50,000		2.470	%	December 13, 2011	February 1, 2015	404		458
Swap	Interest Rate	Cash Flow	(a)	23,000		23,000		2.513	%	December 7-12, 2011	May 1, 2015	221		245
Swap	Interest Rate	Cash Flow	(a)	27,062		27,062		2.750	%	December 21, 2011	September 30, 2017	825		914
Swap	Interest Rate	Cash Flow	(a)	25,774		25,774		3.300	%	December 22, 2011	January 30, 2021	1,003		1,262
Swap	Interest Rate	Cash Flow	(a)	25,774		25,774		3.090	%	January 6, 2012	October 30, 2019	940		1,129
				$	428,610	$	428,610					$	12,383	$	14,210