Acquisitions, Dispositions, Discontinued Operations and Assets Held for Sale Acquisitions, Dispositions, Discontinued Operations and Assets Held for Sale (Income from Discontinued Operations) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Property revenues				$ 19,184
Property expenses				(6,898)
Property revenues less property expenses				12,286
Property management expense				(242)
Depreciation and amortization				(4,327)
Income tax expense				(112)
Income from discontinued operations	$ 0	$ 0	$ 0	$ 7,605