Real Estate Activities - Adeptus Health - Additional Information (Detail) - Adeptus Health [Member] $ in Millions	12 Months Ended
Dec. 31, 2020 USD ($) Facility Lease	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Business Acquisition [Line Items]
Number of leased properties \| Lease	60
Real estate impairment charge	$ 20	$ 2	$ 24
Straight-line rent and other write-off, net of tax	$ 10		$ 6
Number of facilities transitioned \| Facility	18
Maximum [Member]
Business Acquisition [Line Items]
Percentage of vacant on leased property	1.00%

The charge against earnings in the period to reduce the carrying amount of real property to fair value.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109226691&loc=d3e2921-110230

Name:	us-gaap_ImpairmentOfRealEstate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration