Real Estate Assets Real estate sold (Details)	12 Months Ended
	Dec. 31, 2019 USD ($) ft²	Dec. 31, 2018 USD ($) ft²	Dec. 31, 2017 USD ($)
Property, Plant and Equipment [Line Items]
Number of units in real estate property | ft²	477	1,347
Land	$ 635,757,000	$ 519,300,000
Investment Building and Building Improvements	3,256,223,000	2,738,085,000
Furniture, fixtures, and equipment	323,381,000	278,151,000
Real Estate Investment Property, Accumulated Depreciation	(421,551,000)	(272,042,000)
Assets	4,770,560,000	4,410,958,000
Liabilities	2,836,444,000	2,801,573,000
Gains (Losses) on Sales of Investment Real Estate	1,567,000	69,705,000	$ 37,635,000
Income (Loss) before Gain (Loss) on Sale of Properties	$ 100,238,000	70,077,000	$ 59,388,000
McNeil Ranch [Domain]
Property, Plant and Equipment [Line Items]
Number of units in real estate property	192
Land	$ 2,100,000
Investment Building and Building Improvements	16,300,000
Furniture, fixtures, and equipment	2,096,000
Real Estate Investment Property, Accumulated Depreciation	(5,252,000)
Assets	15,244,000
business combination purchase price	30,000,000
Gains (Losses) on Sales of Investment Real Estate	13,900,000
Income (Loss) before Gain (Loss) on Sale of Properties	200,000
Long-term Debt, Gross	$ 13,418,000
Stoneridge Farms at Hunt Club [Member]
Property, Plant and Equipment [Line Items]
Number of units in real estate property	364
Land	$ 3,026,000
Investment Building and Building Improvements	35,740,000
Furniture, fixtures, and equipment	4,305,000
Real Estate Investment Property, Accumulated Depreciation	(6,601,000)
Assets	36,470,000
business combination purchase price	55,000,000
Gains (Losses) on Sales of Investment Real Estate	16,800,000
Income (Loss) before Gain (Loss) on Sale of Properties	600,000
Long-term Debt, Gross	$ 25,626,000
stone rise [Domain]
Property, Plant and Equipment [Line Items]
Number of units in real estate property	216
Land	$ 6,950,000
Investment Building and Building Improvements	18,860,000
Furniture, fixtures, and equipment	3,292,000
Real Estate Investment Property, Accumulated Depreciation	(6,722,000)
Assets	22,380,000
business combination purchase price	42,500,000
Gains (Losses) on Sales of Investment Real Estate	18,600,000
Income (Loss) before Gain (Loss) on Sale of Properties	500,000
Long-term Debt, Gross	$ 23,520,000
Lake Cameron [Member]
Property, Plant and Equipment [Line Items]
Number of units in real estate property	328
Land	$ 4,000,000
Investment Building and Building Improvements	21,519,000
Furniture, fixtures, and equipment	3,687,000
Real Estate Investment Property, Accumulated Depreciation	(7,220,000)
Assets	21,986,000
business combination purchase price	43,500,000
Gains (Losses) on Sales of Investment Real Estate	20,400,000
Income (Loss) before Gain (Loss) on Sale of Properties	200,000
Long-term Debt, Gross	19,736,000
Multifamily Acquisitions [Member]
Property, Plant and Equipment [Line Items]
Land	9,264,000	28,365,000
Investment Building and Building Improvements	87,098,000	181,931,000
Furniture, fixtures, and equipment	19,806,000	44,474,000
business combination purchase price	$ 117,000,000	$ 258,600,000