Discontinued Operations (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2014 property	Dec. 31, 2013 property
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of operating properties sold	11	20
Number of properties held for sale	1	8
Property held for sale	$ 3.8	$ 155.0
Property held for sale, accumulated depreciation	2.3	32.4
Gross property included in discontinued operations		68.6
Accumulated depreciation for property included in discontinued operations		$ 13.2
California [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of operating properties sold		1
Florida [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of operating properties sold	2	3
Number of properties held for sale		2
Georgia [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of operating properties sold	3
Number of properties held for sale		3
Louisiana [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of operating properties sold	2
Nevada [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of operating properties sold		1
New Mexico [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of operating properties sold		2
North Carolina [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of operating properties sold	2	3
Number of properties held for sale		1
Tennessee [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of operating properties sold		1
Texas [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of operating properties sold	2	9
Number of properties held for sale	1	2
Center Sold Not Including Held For Sale [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of operating properties sold	3