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Short-Term Investments (Details) | 12 Months Ended
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Dec. 31, 2015 | Sep. 30, 2014
Short-Term Investments |  |
Maturity Period of certificates of deposit, minimum | 3 months | 3 months
Maturity Period of certificates of deposit, maximum | 1 year | 1 year

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- Definition The latest maturity date when short-term debt instruments are reported on the Schedule of Investments. + References No definition available. + Details
Name: | dwsn_CertificatesOfDepositMaturityPeriodMaximum
Namespace Prefix: | dwsn_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

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- Definition The earliest maturity date when short-term debt instruments are reported on the Schedule of Investments. + References No definition available. + Details
Name: | dwsn_CertificatesOfDepositMaturityPeriodMinimum
Namespace Prefix: | dwsn_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

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