Property Dispositions (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2016 USD ($) property	Mar. 31, 2015 USD ($) property
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Document Period End Date	Mar. 31, 2016
Number of impaired operating properties | property	2
Proceeds from sale of real estate investments	$ 34,321	$ 3,414
Gain (Loss) on Sale of Properties, Net of Applicable Income Taxes	12,868	803
Provision for impairment	$ (866)	$ 0
Number of impaired land parcels | property	1
Wholly Owned Properties [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Limited Liability Company (LLC) or Limited Partnership (LP), Managing Member or General Partner, Ownership Interest	100.00%	100.00%
Parent Company [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of real estate investments	$ 32,261	$ 3,414
Gain (Loss) on Sale of Properties, Net of Applicable Income Taxes	12,868	803
Revenues	149,628	140,399
Operating expenses	95,876	89,839
Provision for impairment	$ 1,666	$ 0
Operating Segments [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of Real Estate Properties Sold | property	3	1
Land [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of Real Estate Properties Sold | property	5	0