DIRECT FINANCING LEASES (Narrative) (Detail)		1 Months Ended			3 Months Ended					12 Months Ended
	Jan. 11, 2019 USD ($) facility	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($) facility	Nov. 27, 2013 USD ($) facility lease	Dec. 31, 2018 USD ($) facility	Sep. 30, 2018 USD ($) facility	Jun. 30, 2018 USD ($) facility	Dec. 31, 2017 USD ($) facility	Sep. 30, 2017 USD ($) facility	Dec. 31, 2019 USD ($) facility	Dec. 31, 2019 USD ($) facility	Dec. 31, 2018 USD ($) facility	Dec. 31, 2017 USD ($) facility	Oct. 31, 2019 facility	Jan. 31, 2019 USD ($)	Jan. 16, 2019 facility	Jul. 31, 2017 facility
Lessee, Lease, Description [Line Items]
Number of real estate properties | facility										987	987
Approximate purchase price											$ 1,325,400,000	$ 105,700,000	$ 412,700,000
Impairment on real estate properties											48,939,000	35,014,000	99,070,000
Rental income											804,076,000	767,340,000	775,176,000
Operating lease, Lease income											804,076,000	767,340,000	775,176,000
Other assets					$ 24,308,000					$ 102,462,000	102,462,000	24,308,000
Impairment on direct financing leases											$ 7,917,000	$ 27,168,000	198,199,000
Orianna
Lessee, Lease, Description [Line Items]
Approximate purchase price				$ 529,000,000
Number of leases | lease				4
Master lease term				50 years
Additional provision for uncollectible accounts					$ 27,200,000
Amortization period	15 years
Interest on lease per annum				10.60%
Orianna | Restructuring Support Agreement ("RSA")
Lessee, Lease, Description [Line Items]
Monthly rent payment under restructuring			$ 1,000,000.0
Amount committed as debtor in possession financing			$ 30,000,000
Operating Lease [Member] | Orianna
Lessee, Lease, Description [Line Items]
Number of real estate properties | facility					3							3
Recorded investment in operating lease					$ 30,500,000							$ 30,500,000
Southeast [Member] | Orianna
Lessee, Lease, Description [Line Items]
Carrying amount of facility Net					$ 120,500,000							120,500,000
Impairment on real estate properties													20,800,000
Outstanding receivable reduction													$ 19,300,000
Allowance for loss under direct financing leases									$ 172,200,000			$ 103,200,000
Southeast [Member] | Direct Financing Leases [Member] | Orianna
Lessee, Lease, Description [Line Items]
Number of real estate properties | facility					15							15
Texas
Lessee, Lease, Description [Line Items]
Approximate purchase price							$ 22,800,000	$ 40,000,000.0	2,300,000
Facilities Sold
Lessee, Lease, Description [Line Items]
Number of real estate properties | facility					78			52				78	52
Facilities Sold | Direct Financing Leases [Member] | Orianna
Lessee, Lease, Description [Line Items]
Number of real estate properties | facility								8					8
Facilities Acquired [Member]
Lessee, Lease, Description [Line Items]
Number of real estate properties | facility														60
Facilities Owned and Leased [Member] | Operating Lease [Member] | Orianna
Lessee, Lease, Description [Line Items]
Number of real estate properties | facility					3							3
Facilities Transitioned to Other Operators [Member] | Orianna | Five Existing Operators [Member]
Lessee, Lease, Description [Line Items]
Number of real estate properties | facility						22
Facilities Transitioned to Other Operators [Member] | Orianna | Restructuring Support Agreement ("RSA")
Lessee, Lease, Description [Line Items]
Number of real estate properties | facility			23
Facilities Held for Sale or Closed [Member]
Lessee, Lease, Description [Line Items]
Number of real estate properties | facility										6	6
Facilities Held for Sale or Closed [Member] | Orianna | Restructuring Support Agreement ("RSA")
Lessee, Lease, Description [Line Items]
Number of real estate properties | facility			19
Skilled Nursing Facilities
Lessee, Lease, Description [Line Items]
Number of real estate properties | facility					12					784	784	12
Skilled Nursing Facilities | Orianna
Lessee, Lease, Description [Line Items]
Number of real estate properties | facility				55
Skilled Nursing Facilities | Texas
Lessee, Lease, Description [Line Items]
Number of real estate properties | facility							5
Skilled Nursing Facilities | Facilities Sold
Lessee, Lease, Description [Line Items]
Number of real estate properties | facility					1							1
Carrying amount of facility					$ 15,400,000							$ 15,400,000
Total proceeds												$ 15,400,000
Skilled Nursing Facilities | Facilities Sold | Orianna | Distribution Trust [Member]
Lessee, Lease, Description [Line Items]
Number of real estate properties | facility																15
Skilled Nursing Facilities | Facilities Sold | Direct Financing Leases [Member] | Orianna
Lessee, Lease, Description [Line Items]
Number of real estate properties | facility						1
Skilled Nursing Facilities | Facilities Acquired [Member]
Lessee, Lease, Description [Line Items]
Number of real estate properties | facility								31		89	89		31
Skilled Nursing Facilities | Facilities Acquired [Member] | Texas
Lessee, Lease, Description [Line Items]
Number of real estate properties | facility								6					6
Skilled Nursing Facilities | Facilities Transitioned to Other Operators [Member]
Lessee, Lease, Description [Line Items]
Number of real estate properties | facility																	9
Skilled Nursing Facilities | Facilities Transitioned to Other Operators [Member] | Texas | Orianna
Lessee, Lease, Description [Line Items]
Number of real estate properties								9					9
Assisted Living Facilities
Lessee, Lease, Description [Line Items]
Number of real estate properties | facility										114	114
Assisted Living Facilities | Orianna
Lessee, Lease, Description [Line Items]
Number of real estate properties | facility				1
Assisted Living Facilities | Facilities Acquired [Member]
Lessee, Lease, Description [Line Items]
Number of real estate properties | facility										4	4
Skilled Nursing Facilities and Headquarters [Member] | Orianna
Lessee, Lease, Description [Line Items]
Carrying amount of facility						$ 5,500,000
Total proceeds						5,500,000
8 Facilities | Facilities Sold | Direct Financing Leases [Member] | Orianna
Lessee, Lease, Description [Line Items]
Carrying amount of facility								$ 36,400,000					$ 36,400,000
Proceeds from sale of facility													33,300,000
8 Facilities | Facilities Sold | Northwest [Member] | Direct Financing Leases [Member] | Orianna | Sales Agreement [Member]
Lessee, Lease, Description [Line Items]
Impairment on real estate properties													3,300,000
9 Facilities [Member] | Facilities Transitioned to Other Operators [Member] | Texas | Orianna
Lessee, Lease, Description [Line Items]
Impairment on real estate properties													1,800,000
Written down value of direct financing lease assets to original cost													$ 19,000,000.0
15 Skilled Nursing Facilities [Member] | Orianna
Lessee, Lease, Description [Line Items]
Cash consideration sale of productive assets	$ 146,000,000
15 Skilled Nursing Facilities [Member] | Direct Financing Leases [Member] | Orianna
Lessee, Lease, Description [Line Items]
Interest rate	6.00%
Aggregate consideration	$ 176,000,000
Cash consideration sale of productive assets										$ 94,000,000
Other investments, gross	$ 30,000,000.0
Other assets										14,000,000	$ 14,000,000				$ 115,800,000
Impairment on direct financing leases		$ 7,700,000
Assets Held-in-trust										$ 14,000,000	$ 14,000,000
15 Skilled Nursing Facilities [Member] | Facilities Sold | Direct Financing Leases [Member] | Orianna
Lessee, Lease, Description [Line Items]
Number of real estate properties | facility	15
22 Facilities | Facilities Transitioned to Other Operators [Member] | Five Existing Operators [Member]
Lessee, Lease, Description [Line Items]
Rental income						16,800,000
Operating lease, Lease income						16,800,000
22 Facilities | Facilities Transitioned to Other Operators [Member] | Orianna | Five Existing Operators [Member]
Lessee, Lease, Description [Line Items]
Carrying amount of facility Net						$ 184,500,000
38 Facilities | Southeast [Member] | Orianna | Minimum
Lessee, Lease, Description [Line Items]
Fair value of annual rents									$ 32,000,000.0
Rental yields									9.00%
38 Facilities | Southeast [Member] | Orianna | Maximum
Lessee, Lease, Description [Line Items]
Fair value of annual rents									$ 38,000,000.0
Rental yields									10.00%
Recorded Allowance On Direct Finance Lease [Member] | Southeast [Member] | Orianna
Lessee, Lease, Description [Line Items]
Number of real estate properties | facility									38