Total number of share held by related party.

No definition available.

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Namespace Prefix:	tls_
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- Definition

Amount of interest expense incurred on a debt or other obligation to related party.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
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- Definition

The cash inflow from a long-term borrowing made from related parties where one party can exercise control or significant influence over another party; including affiliates, owners or officers and their immediate families, pension trusts, and so forth. Alternate caption: Proceeds from Advances from Affiliates.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3255-108585

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of transactions with related party during the financial reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39603-107864

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- 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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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Identify the stated interest rate per the agreement, for example, leasing and debt arrangements between related parties.

+ References

No definition available.

+ Details

Name:	us-gaap_RelatedPartyTransactionRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

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- Details

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- Details

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- Details

Name:	us-gaap_RelatedPartyTransactionAxis=tls_SubordinatedLoanAgreementsAndPromissoryNotesMember
Namespace Prefix:
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- Details

Name:	srt_OwnershipAxis=tls_TelosCorporationMember
Namespace Prefix:
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Related Party Transactions (Details) - USD ($) $ in Thousands				3 Months Ended		9 Months Ended
	Apr. 18, 2017	Apr. 17, 2017	Mar. 31, 2015	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Emmett J. Wood
Related Party Transaction [Line Items]
Related party transaction, amounts of transaction				$ 88	$ 193	$ 389	$ 517
Number of shares held by related party (in shares)				73,562		73,562		682,502,000,000
Affiliated Entity \| Porter \| Subordinated Loan Agreements and Promissory Notes
Related Party Transaction [Line Items]
Proceeds from related party, debt			$ 2,500
Related party transaction, rate	6.00%	12.00%	12.00%
Interest expense, related party					$ 90		$ 265
Affiliated Entity \| Porter \| Telos Corporation \| Subordinated Loan Agreements and Promissory Notes
Related Party Transaction [Line Items]
Noncontrolling interest, ownership percentage by noncontrolling owners			35.00%