Debt (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012
Mortgage Loans Payable
Interest rate, description	LIBOR plus 3%
Mortgage loans payable	$ 278,824	$ 280,576
Amherst, NY [Member] | Five Point Six Five Percent Loan Due October Two Thousand and Thirteen [Member]
Mortgage Loans Payable
Maturity	Oct 2013
Interest rate, description
Interest rate	5.65%
Mortgage loans payable	15,104	15,225
Memphis, TN [Member] | Three Percent Loan Due August Two Thousand and Fourteen [Member]
Mortgage Loans Payable
Maturity	Aug 2014
Interest rate, description	Libor + 2.5%
Interest rate	3.00%
Mortgage loans payable	13,337	13,408
Lisle, IL [Member] | Two Point Seven One Percent Loan Due October Two Thousand and Fourteen [Member]
Mortgage Loans Payable
Maturity	Oct 2014
Interest rate, description	Libor + 2.5 %
Interest rate	2.71%
Mortgage loans payable	5,752	5,752
Lisle, IL [Member] | Five Point Five Five Percent Loans Due March Two Thousand Seventeen [Member]
Mortgage Loans Payable
Maturity	Mar 2017
Interest rate, description
Interest rate	5.55%
Mortgage loans payable	5,524	5,543
Chicago, IL [Member] | Six Point Two Five Percent Loan Due April Two Thousand and Fifteen [Member]
Mortgage Loans Payable
Maturity	Apr 2015
Interest rate, description
Interest rate	6.25%
Mortgage loans payable	8,700	8,700
Chicago, IL [Member] | Five Point Seven Five Percent Loan Due March Two Thousand and Sixteen [Member]
Mortgage Loans Payable
Maturity	Mar 2016
Interest rate, description
Interest rate	5.75%
Mortgage loans payable	20,112	20,200
Houston, TX [Member] | Six Point One Two Percent Loan Due April Two Thousand and Sixteen [Member]
Mortgage Loans Payable
Maturity	Apr 2016
Interest rate, description
Interest rate	6.12%
Mortgage loans payable	50,896	52,052
New York, NY [Member] | Three Point Five Percent Due May Two Thousand Sixteen [Member]
Mortgage Loans Payable
Maturity	May 2016
Interest rate, description	Libor + 2.5%
Interest rate	3.50%
Mortgage loans payable	51,982	51,982
Greensboro, NC [Member] | Six Point Two Two Percent Loan Due August Two Thousand and Sixteen [Member]
Mortgage Loans Payable
Maturity	Aug 2016
Interest rate, description
Interest rate	6.22%
Mortgage loans payable	15,039	15,139
Cerritos, CA [Member] | Five Point Zero Seven Percent Loan Due January Two Thousand and Seventeen [Member]
Mortgage Loans Payable
Maturity	Jan 2017
Interest rate, description
Interest rate	5.07%
Mortgage loans payable	23,174	23,184
Orlando, FL [Member] | Six Point Four Zero Percent Loans Due July Two Thousand Seventeen [Member]
Mortgage Loans Payable
Maturity	Jul 2017
Interest rate, description
Interest rate	6.40%
Mortgage loans payable	37,426	37,580
Plantation, FL [Member] | Six Point Four Eight Percent Loans Due April Two Thousand Eighteen [Member]
Mortgage Loans Payable
Maturity	Apr 2018
Interest rate, description
Interest rate	6.48%
Mortgage loans payable	10,778	10,811
Meriden CT [Member] | Three Point Nine Five Percent Loan Due October Two Thousand and Twenty Two [Member]
Mortgage Loans Payable
Maturity	Oct 2022
Interest rate, description
Interest rate	3.95%
Mortgage loans payable	$ 21,000	$ 21,000