SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Narrative 2) (Detail)			12 Months Ended
	Jan. 01, 2019 USD ($)	Feb. 01, 2016 USD ($) facility	Dec. 31, 2018 USD ($) segment facility $ / shares	Dec. 31, 2017 USD ($) facility $ / shares	Dec. 31, 2016 USD ($) facility	Mar. 31, 2018 USD ($)	Jan. 01, 2018 USD ($)	Apr. 01, 2015 $ / shares
Accounting Policies [Line Items]
Unamortized direct costs related to origination of direct financing leases			$ 0	$ 0
Impairment on real estate properties			29,839,000	99,070,000	$ 58,726,000
Loan loss reserves			108,100,000	177,500,000
Equity method investment, other than temporary impairment			0	0	0
Cash, FDIC insured amount			250,000
Payment made to operator to buyout out in money purchase option			50,000,000
Amount of lease inducement that will be amortized as a reduction to rental income			49,644,000	16,812,000		$ 28,000,000
Accrued expenses and other liabilities			272,172,000	295,142,000
Provisions for uncollectible accounts			6,689,000	14,580,000	9,845,000
Recovery of provisions for other losses			4,800,000
Impairment of goodwill			$ 0	0	0
Number of Operating Segments | segment			1
Provision of of straight-line rent and contractual receivables			$ 11,500,000
Annual percentage increases over the rents of the prior year, minimum			2.00%
Annual percentage increases over the rents of the prior year, maximum			3.00%
Amortization of financing cost			$ 8,960,000	$ 9,516,000	9,345,000
Common stock, par value (in dollars per share) | $ / shares			$ 0.10	$ 0.10				$ 0.10
Number of facilities owned | facility			924
Purchase price of buildings acquired paid in cash			$ 105,700,000	$ 412,700,000	1,022,800,000
Net cash provided by (used in) operating activities			499,373,000	577,912,000	624,773,000
Increase in cash, cash equivalents, and restricted cash			$ (85,137,000)	(10,468,000)	87,245,000
Contractual Receivable [Member]
Accounting Policies [Line Items]
Provisions for uncollectible accounts				9,300,000
Straight-Line Rent Receivable [Member]
Accounting Policies [Line Items]
Provisions for uncollectible accounts				$ 4,100,000	$ 4,300,000
Accounting Standards Update 2014-09 [Member]
Accounting Policies [Line Items]
Deferred gain resulting from sale of facilities to third party through retained earnings							$ 10,000,000
Accounting Standards Update 2016-02 [Member] | Scenario Forecast Adjustment [Member] | Minimum
Accounting Policies [Line Items]
Operating lease, right of use asset	$ 10,000,000
Lease liability	10,000,000
Rental income	12,000,000
Rental expense	12,000,000
Accounting Standards Update 2016-02 [Member] | Scenario Forecast Adjustment [Member] | Maximum
Accounting Policies [Line Items]
Operating lease, right of use asset	12,000,000
Lease liability	12,000,000
Rental income	20,000,000
Rental expense	$ 20,000,000
Skilled Nursing Facilities
Accounting Policies [Line Items]
Number of facilities owned | facility			12	31	70
Skilled Nursing Facilities | Laurel Healthcare Holdings [Member]
Accounting Policies [Line Items]
Number of facilities owned | facility		10
Purchase price of buildings acquired paid in cash		$ 169,000,000
Cash Flow Hedging [Member]
Accounting Policies [Line Items]
Cash flow hedges recorded at fair value			$ 4,000,000	$ 1,500,000
Omega OP
Accounting Policies [Line Items]
Percentage of limited partnership interests owned			96.00%
Laurel Healthcare Holdings [Member] | Skilled Nursing Facilities
Accounting Policies [Line Items]
Percentage of ownership interest		34.00%
Omega Op Units [Member] | Omega OP
Accounting Policies [Line Items]
Percentage of limited partnership interests owned			96.00%
Other Investors | Omega OP
Accounting Policies [Line Items]
Percentage of limited partnership interests owned			4.00%