Debt (Details Textual) (KeyBanc Capital Markets and J.P. Morgan Securities LLC [Member], USD $)	0 Months Ended	9 Months Ended
	May 08, 2014	Sep. 30, 2014	Dec. 31, 2013	Nov. 05, 2013
Mortgages, Notes and Margins Payable (Textual) [Abstract]
Maximum borrowing amount				$ 500,000,000
Term Loan [Member]
Mortgages, Notes and Margins Payable (Textual) [Abstract]
Debt instrument, amount				200,000,000
Interest rate at period end on unsecured term loan		1.66%	1.67%
Debt Instrument, Maturity Date		May 07, 2017
Revolving Credit Facility [Member]
Mortgages, Notes and Margins Payable (Textual) [Abstract]
Maximum borrowing amount				300,000,000
Potential borrowing capacity				800,000,000
Extension option on line of credit, period		1 year
Notice Period Provided for One Year Extension Option on Revolving LIne of Credit		60
Commitment fee	0.20%
Interest rate at period end on revolving line of credit		1.76%	1.60%
Remaining borrowing capacity		$ 300,000,000	$ 299,820,000
Line of Credit Facility, Expiration Date		May 07, 2016