Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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-Name Accounting Standards Codification
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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Acquisitions - Goodwill (Details) - USD ($) $ in Thousands	Jun. 22, 2020	Jun. 18, 2020	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019
Total goodwill recognized			$ 72,387	$ 71,822	$ 70,262	$ 8,673	$ 8,842	$ 8,606	$ 8,961	$ 8,886
Giner ELX, Inc
Consideration paid	$ 52,873
Less: net assets acquired	(26,680)
Total goodwill recognized	$ 26,193
United Hydrogen Group Inc
Consideration paid		$ 50,813
Less: net assets acquired		(14,339)
Total goodwill recognized		$ 36,474