Investments in Unconsolidated Ventures - Changes in Carrying Value (Details)	1 Months Ended		3 Months Ended		6 Months Ended
	Mar. 31, 2019 USD ($) facility	Oct. 31, 2018 USD ($)	Jun. 30, 2019 USD ($) facility	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($) facility	Jun. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)	Nov. 01, 2018	Dec. 31, 2015
Schedule of Equity Method Investments [Line Items]
Equity in Earnings (Losses)			$ (4,405,000)	$ (4,098,000)	$ (4,629,000)	$ (12,724,000)
Select Revenues and Expenses, net			(12,409,000)	(13,504,000)	(22,493,000)	(31,289,000)
Cash Distributions			5,132,000	3,440,000	12,079,000	6,325,000
Carrying Value			288,907,000		288,907,000		$ 264,319,000
Eclipse
Schedule of Equity Method Investments [Line Items]
Equity in Earnings (Losses)			(232,000)	75,000	(332,000)	80,000
Select Revenues and Expenses, net			(622,000)	(442,000)	(1,152,000)	(842,000)
Cash Distributions			208,000	191,000	287,000	445,000
Carrying Value			11,147,000		11,147,000		11,765,000
Capitalized acquisition costs			$ 1,300,000		$ 1,300,000
Properties | facility			76		76
Ownership interest (as a percentage)			5.60%		5.60%
Envoy
Schedule of Equity Method Investments [Line Items]
Equity in Earnings (Losses)			$ 0	(366,000)	$ 96,000	(368,000)
Select Revenues and Expenses, net			(12,000)	(363,000)	(822,000)	(364,000)
Cash Distributions			38,000	0	4,339,000	0
Carrying Value			474,000		474,000		4,717,000
Properties | facility	11
Proceeds from sale of held-for-sale property	$ 118,000,000
Griffin-American
Schedule of Equity Method Investments [Line Items]
Equity in Earnings (Losses)			(3,433,000)	(1,843,000)	(4,028,000)	(1,887,000)
Select Revenues and Expenses, net			(6,229,000)	(5,126,000)	(9,812,000)	(8,812,000)
Cash Distributions			3,435,000	1,706,000	4,551,000	2,422,000
Carrying Value			141,930,000		141,930,000		113,982,000
Capitalized acquisition costs			$ 13,400,000		$ 13,400,000
Properties | facility			250		250
Ownership interest (as a percentage)			14.30%		14.30%
Espresso
Schedule of Equity Method Investments [Line Items]
Equity in Earnings (Losses)			$ (1,771,000)	(2,651,000)	$ (2,367,000)	(11,555,000)
Select Revenues and Expenses, net			(2,217,000)	(3,794,000)	(4,050,000)	(13,686,000)
Cash Distributions			0	0	0	0
Carrying Value			0		0		0
Capitalized acquisition costs			$ 7,600,000		$ 7,600,000
Properties | facility			155		155
Ownership interest (as a percentage)			36.70%		36.70%
Trilogy
Schedule of Equity Method Investments [Line Items]
Equity in Earnings (Losses)			$ 1,037,000	640,000	$ 2,032,000	898,000
Select Revenues and Expenses, net			(3,329,000)	(3,779,000)	(6,657,000)	(7,585,000)
Cash Distributions			1,451,000	1,451,000	2,902,000	3,366,000
Carrying Value			135,294,000		135,294,000		133,764,000
Capitalized acquisition costs			$ 9,800,000		$ 9,800,000
Properties | facility			77		77
Ownership interest sold (as a percentage)		20.00%
Proceeds from sale of equity method investments		$ 48,000,000
Ownership interest (as a percentage)		29.00%	23.20%		23.20%			23.00%	29.00%
Eclipse, Envoy, Griffin-American, Espresso, Trilogy
Schedule of Equity Method Investments [Line Items]
Equity in Earnings (Losses)			$ (4,399,000)	(4,145,000)	$ (4,599,000)	(12,832,000)
Select Revenues and Expenses, net			(12,409,000)	(13,504,000)	(22,493,000)	(31,289,000)
Cash Distributions			5,132,000	3,348,000	12,079,000	6,233,000
Carrying Value			288,845,000		288,845,000		264,228,000
Operator Platform
Schedule of Equity Method Investments [Line Items]
Equity in Earnings (Losses)			(6,000)	47,000	(30,000)	108,000
Select Revenues and Expenses, net			0	0	0	0
Cash Distributions			0	$ 92,000	0	$ 92,000
Carrying Value			$ 62,000		$ 62,000		$ 91,000
Properties | facility			0		0
Ownership interest (as a percentage)			20.00%		20.00%