GOODWILL AND OTHER INTANGIBLE ASSETS, NET - Activity Related to Other Intangible Assets, Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Intangible Assets [Line Items]
Non-cash impairment charge for write-off of intangible assets			$ 1,300
Intangible assets, accumulated amortization	$ 7,044	$ 693
Intangible Assets [Roll Forward]
Beginning balance	44,132	46,100
Additions	28,900	500
Write-off	(1,500)
Amortization	(6,800)	(2,500)
Ending balance	64,748	44,132	46,100
Noncompete Agreements [Member]
Intangible Assets [Line Items]
Intangible assets, accumulated amortization	$ 5,000
Weighted-average amortization period	1 year 6 months
Intangible Assets [Roll Forward]
Beginning balance	$ 600	2,800
Additions	5,200	300
Write-off	0
Amortization	(2,400)	(2,500)
Ending balance	$ 3,400	600	2,800
Amortizable acquired names [Member]
Intangible Assets [Line Items]
Weighted-average amortization period	1 year 2 months 12 days
Intangible Assets [Roll Forward]
Beginning balance	$ 0	0
Additions	10,000	0
Write-off	0
Amortization	(4,400)	0
Ending balance	5,600	0	0
Acquired Names [Member]
Intangible Assets [Line Items]
Non-cash impairment charge for write-off of intangible assets	1,500
Unamortizable acquired names [Member]
Intangible Assets [Roll Forward]
Beginning balance	19,600	19,600
Additions	0	0
Write-off	(1,500)
Amortization	0	0
Ending balance	18,100	19,600	19,600
Certificates of Need and Licenses [Member]
Intangible Assets [Roll Forward]
Beginning balance	23,900	23,700
Additions	13,700	200
Write-off	0
Amortization	0	0
Ending balance	$ 37,600	$ 23,900	$ 23,700