Leases - Finance leases (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Fixed assets:
Property and equipment - gross	$ 1,512,304	$ 1,521,906
Accumulated depreciation and amortization	(725,037)	(673,578)
Property and equipment - net	787,267	848,328
Finance leases
Fixed assets:
Property and equipment - gross	75,318	75,322
Accumulated depreciation and amortization	(57,684)	(55,547)
Property and equipment - net	$ 17,634	$ 19,775

Amount, before accumulated depreciation and amortization, of property, plant, and equipment and finance lease right-of-use asset.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(13))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123391704&loc=SL77918627-209977

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