Property Dispositions (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017 USD ($) property	Sep. 30, 2016 USD ($) property	Sep. 30, 2017 USD ($) property	Sep. 30, 2016 USD ($) property
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of real estate investments	$ 167	$ 47,180	$ 15,397	$ 85,885
Gain (Loss) on Sale of Properties, Net of Applicable Income Taxes	131	9,580	4,913	22,997
Provision for impairment	$ 0	$ 0	$ 0	$ (1,666)
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	0.00%	100.00%	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			$ 15,397	$ 83,675
Gain (Loss) on Sale of Properties, Net of Applicable Income Taxes	$ 131	$ 9,580	4,913	22,997
Revenues	262,141	152,768	719,576	454,810
Operating expenses	177,203	98,228	558,520	293,675
Provision for impairment	$ 0	$ 0	$ 0	$ (1,666)
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	0	3	1	7
Land [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of Real Estate Properties Sold | property	0	2	7	12