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Short-Term Investments (Details)	12 Months Ended
	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

X

- 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

X

- 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

X

- References

No definition available.

+ Details

Name:	invest_InvestmentsScheduleAbstract
Namespace Prefix:	invest_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration