IMPAIRMENT OF REAL ESTATE AND DISPOSITIONS (Details)		9 Months Ended	10 Months Ended	12 Months Ended
	Apr. 01, 2019 facility	Dec. 31, 2019 USD ($) facility	Jan. 31, 2020 facility	Dec. 31, 2019 USD ($) facility	Dec. 31, 2018 USD ($) facility	Dec. 31, 2017 USD ($) facility
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment losses on real estate investments				$ 121,819,000	$ 1,413,000	$ 1,326,000
Skilled Nursing Transitional Care Facilities and Senior Housing Facilities
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment losses on real estate investments				$ 26,600,000
Skilled Nursing/Transitional Care
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties impaired | facility				6
Senior Housing Communities
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties impaired | facility				4
Disposed by Sale | Skilled Nursing/Transitional Care
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties impaired | facility						1
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Skilled Nursing/Transitional Care
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment losses on real estate investments					$ 900,000
Number of properties with impairment | facility					1
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Senior Housing Communities
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of properties with impairment | facility						1
2019 Dispositions
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment losses on real estate investments				$ 95,200,000
2019 Dispositions | Senior Care Centers Facilities
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties impaired | facility				3
2019 Dispositions | Disposal Group, Disposed of by Sale, Not Discontinued Operations | Skilled Nursing Transitional Care Facilities and Senior Housing Facilities
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Aggregate consideration received		$ 323,600,000		$ 323,600,000
Carrying value of assets and liabilities received		$ 321,300,000		321,300,000
Gain (loss) on sale				2,300,000
Net income (loss) on discontinued operations				$ 2,200,000	$ 19,100,000	$ 13,000,000.0
2019 Dispositions | Disposal Group, Disposed of by Sale, Not Discontinued Operations | Skilled Nursing/Transitional Care
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of properties sold | facility		5		39
2019 Dispositions | Disposal Group, Disposed of by Sale, Not Discontinued Operations | Senior Housing Communities
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of properties sold | facility				7
2018 Dispositions | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Aggregate consideration received					382,600,000
Carrying value of assets and liabilities received					254,400,000
Gain (loss) on sale					128,200,000
Net income (loss) on discontinued operations					$ 23,600,000	47,100,000
2018 Dispositions | Disposal Group, Disposed of by Sale, Not Discontinued Operations | Skilled Nursing/Transitional Care
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of properties sold | facility					51
2018 Dispositions | Disposal Group, Disposed of by Sale, Not Discontinued Operations | Senior Housing Communities
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment losses on real estate investments					$ 500,000
Number of properties sold | facility					6
Number of properties with impairment | facility					1
2018 Dispositions | Disposal Group, Disposed of by Sale, Not Discontinued Operations | Senior Housing - Managed
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of properties sold | facility					1
2017 Dispositions | Disposed by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Aggregate consideration received						150,200,000
Carrying value of assets and liabilities received						98,200,000
Gain (loss) on sale						$ 52,000,000.0
2017 Dispositions | Disposed by Sale | Skilled Nursing/Transitional Care
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of properties sold | facility						31
2017 Dispositions | Disposed by Sale | Senior Nursing Facilities and Land
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net income (loss) on discontinued operations						$ 12,600,000
Senior Care Centers | 2019 Dispositions | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of properties sold | facility	28
Senior Care Centers | 2019 Dispositions | Disposal Group, Disposed of by Sale, Not Discontinued Operations | Subsequent Event
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of properties sold | facility			2