Amount after tax of gain (loss) not previously recognized resulting from the disposal of a discontinued operation.

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Name:	us-gaap_DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Discontinued Operations - Narrative (Details) - USD ($) $ in Thousands		12 Months Ended
	Sep. 04, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loss from discontinued operations		$ 18,241	$ 5,406	$ 582
Test and Inspection Services
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from divestiture of businesses	$ 4,000
Loss from discontinued operations	$ 10,034