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v3.20.4

Short-Term Investments (Details) | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019
Minimum |  |
Maturity period of certificates of deposit | 3 months | 3 months
Maximum |  |
Maturity period of certificates of deposit | 1 year | 1 year

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- Definition Remaining maturity of certificates of deposit, in 'PnYnMnDTnHnMnS' format. + References No definition available. + Details
Name: | dwsn_CertificatesOfDepositMaturityPeriod
Namespace Prefix: | dwsn_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

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- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |