Other Income (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended	12 Months Ended
Aug. 31, 2019	Sep. 30, 2020	Jun. 30, 2019	Dec. 31, 2020
Other Income
Proceeds from Insurance Policy		$ 1,000		$ 1,000
Cash received from settlement of a working capital adjustment dispute	$ 8,900
Other income relating to a change in estimate of its cylinder deposit liability account			$ 500

Amount of cash inflow for proceeds from settlement of corporate-owned life insurance policy, classified as investing activities. Includes, but is not limited to, bank-owned life insurance policy.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 21C
-URI http://asc.fasb.org/extlink&oid=121586364&loc=SL94080552-108585

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3179-108585

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