Covenants and Events of Default (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015
Debt Instrument [Line Items]
Long-term Debt, Excluding Current Maturities	$ 240,715	$ 244,323	$ 269,594
Covenant Compliance	As of September 30, 2016, we were in compliance with the covenants contained in our note purchase agreement governing our 2019 Notes and Credit Agreement. We are not aware of any non-compliance by any of our unconsolidated real estate entities with the covenants contained in their debt agreements.
Term Loan [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 96,300
Long term portion of term loan	91,300
Short term portion of term loan	5,000
Senior Notes [Member] | 2019 Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 160,000
Debt Instrument, Interest Rate, Stated Percentage	6.11%
Debt, Current	$ 40,000
Long-term Debt, Excluding Current Maturities	30,000
Line of Credit [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	296,300
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	200,000
Term Loan Sublimit for Letters of Credit [Member] [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	100,000
Senior Notes [Member] | 2019 Notes [Member]
Debt Instrument [Line Items]
Short Term Portion of the Senior Notes Payable	10,000
Long Term Portion of the Senior Notes Payable	$ 150,000