Amount of investment in marketable security, classified as noncurrent.

No definition available.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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- Definition

Price of a single share of a number of saleable stocks of a company.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of unrealized gain (loss) on investment.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3602-108585

+ Details

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- Definition

The number of shares held in the investment in marketable securities.

+ References

No definition available.

+ Details

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Namespace Prefix:	usx_
Data Type:	xbrli:sharesItemType
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- Details

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Namespace Prefix:
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Balance Type:
Period Type:

Investments (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Apr. 15, 2021	Mar. 31, 2021
Equity and Other Investments:
Investment in equity securities	$ 500			$ 5,000
Number of shares held				353,604
Unrealized loss (gain) on investment	$ (60)	$ (8,363)
TuSimple
Equity and Other Investments:
Share price			$ 40.00