Real Estate (Held For Sale) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($) property	Dec. 31, 2015 USD ($) property	Dec. 31, 2014 property
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of properties classified as held for sale | property	16	21
Land and improvements	$ 14,114	$ 23,024
Building and improvements	15,446	43,327
Real estate held for sale, gross	29,560	66,351
Less impairment	(2,748)	(2,003)
Real estate held for sale, net	$ 23,850	$ 57,527
Discontinued operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of sold properties | property	0	0	2
Assets Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Less accumulated depreciation and amortization	$ (2,962)	$ (6,821)
Assets Held-for-sale | Discontinued operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of sold properties | property	5