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v3.19.3.a.u2

Short-Term Investments (Details) | 12 Months Ended
--- | ---
Dec. 31, 2019 | Dec. 31, 2018
Minimum |  |
Investments |  |
Maturity period of certificates of deposit | 3 months | 3 months
Maximum |  |
Investments |  |
Maturity period of certificates of deposit | 1 year | 1 year

X
- 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

X
- References No definition available. + Details
Name: | invest_InvestmentLineItems
Namespace Prefix: | invest_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- 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: |