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Commitments and Contingencies - Letters of Credit (Details) - Dec. 31, 2020 - Dominion Letters of Credit | Total | USD ($) | item
--- | --- | --- | ---
Commitment and Contingencies |  |  |
Number of letters of credit | 1 |  | 1
Amount of letter of credit |  | $ 583,000 |

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- Definition Represents the number of letters of credit issued and outstanding. + References No definition available. + Details
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Namespace Prefix: | dwsn_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

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- Definition Face (par) amount of debt instrument at time of issuance. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=119993939&loc=d3e28551-108399 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400 + Details
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Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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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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- Details
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Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |