Real Estate and Other Activities - Disposals - Additional Information (Detail) $ in Millions	6 Months Ended
Jun. 30, 2021 USD ($) Facility	Jun. 30, 2020 USD ($) Facility Property
Business Combinations [Abstract]
Number of facilities sold \| Facility	5	5
Number of properties sold \| Property		4
Proceeds from sale of facilities	$ 25.0	$ 79.0
Gain (loss) on real estate dispositions	$ (0.4)	$ (1.8)

Cash received for the sale of real estate that is not part of an investing activity during the current period.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3179-108585

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