Investment in Real Estate Investment in Real Estate - Real Estate Disposals (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Community base rental income	$ 442,046	$ 426,886	$ 409,801
Rental home income	14,012	14,827	14,267
Utility and other income	76,153	70,209	63,800
Consolidated income from discontinued operations	$ 0	$ 0	48,658
Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Community base rental income			11,565
Rental home income			1,948
Utility and other income			1,384
Discontinued property operating revenues			14,897
Property operating expenses			6,126
Income from discontinued property operations			8,771
Loss from home sales operations			(78)
Other income and expenses			332
Interest and amortization			355
Depreciation and in place lease amortization			1,537
Consolidated income from discontinued operations			$ 7,133