Acquisitions and Dispositions - Additional Information (Detail) $ in Thousands	9 Months Ended
Sep. 30, 2018 USD ($) Hospital	Sep. 30, 2017 USD ($) Hospital
Business Acquisition [Line Items]
Number of hospitals purchased \| Hospital	2	7
Proceeds from sale of business	$ 802,000	$ 24,000
Real Estate and Other Investments [Member]
Business Acquisition [Line Items]
Pretax gain (loss) on sales of business	48,000	10,000
Proceeds from sale of business	44,000	24,000
Discontinued Operations, Disposed of by Sale [Member] \| Oklahoma [Member]
Business Acquisition [Line Items]
Pretax gain (loss) on sales of business	372,000
Proceeds from sale of business	$ 758,000
Number of hospitals sold \| Hospital	2
Hospitals [Member]
Business Acquisition [Line Items]
Aggregate purchase price	$ 788,000	1,000,000
Nonhospital Health Care [Member]
Business Acquisition [Line Items]
Aggregate purchase price	268,000	142,000
Other [Member]
Business Acquisition [Line Items]
Fair value of identifiable net assets of acquired entities	$ 433,000	$ 655,000

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The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

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