Indebtedness Secured Debt (Details) (USD $)	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Debt Instrument [Line Items]
Repayments of Secured Debt	$ 112,097,000	$ 107,240,000
Fixed Rate Secured Debt [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage Rate Range, Minimum	3.50%
Debt Instrument, Interest Rate, Effective Percentage Rate Range, Maximum	4.90%
number of secured loans repaid	9
Repayments of Secured Debt	100,100,000
Repaid Debt, Weighted Average Interest Rate	5.66%
Number Of Secured Loans Assumed In Property Acquisition	3
Debt Instrument, Face Amount	99,300,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-term Debt	$ 103,600,000
Assumed Debt - Weighted Average Remaining Term	1 year 9 months 9 days
Debt, Weighted Average Interest Rate	5.59%
Debt Instrument, Interest Rate, Effective Percentage	3.00%