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Short-Term Investments (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
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:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: