Sales-Type Leases (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Leases [Abstract]
Equipment sales	$ (1,142)	$ 383	$ 4,070	$ 3,528
Cost of equipment sales	(1,400)	118	1,417	2,906
Gross profit	258	265	2,653	622
Sales-type lease, rental contracts	1,400	1,600	4,400	5,300
Interest income	$ 400	$ 900	$ 700	$ 3,200

Cost of Goods Sold (Reversal), Sales-type Lease

No definition available.

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Period Type:	duration

- Definition

Sales-type Lease, Interest Income (Reversal), Lease Receivable

+ References

No definition available.

+ Details

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Balance Type:	credit
Period Type:	duration

- Definition

Sales-Type Lease, Revenue (Reversal)

+ References

No definition available.

+ Details

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Namespace Prefix:	ctos_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Amount of profit (loss) recognized at commencement from sales-type lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 270
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6A
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482964/270-10-50-6A

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479773/842-30-50-5

+ Details

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

- Definition

Amount of sales-type lease income from variable lease payments paid and payable to lessor, excluding amount included in measurement of lease receivable.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479773/842-30-50-5

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 270
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6A
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482964/270-10-50-6A

+ Details

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Balance Type:	credit
Period Type:	duration