Fair Value Measurements. (Details) - USD ($)	Sep. 30, 2021	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Property and equipment held-for-sale at fair value	$ 20,535,000	$ 48,548,000

Fair value portion of assets classified as held for sale.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258

Name:	us-gaap_AssetsHeldForSaleLongLivedFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant