Number of shares of equity interests issued or issuable to acquire entity.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)(4)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

+ Details

Name:	us-gaap_BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

Name:	us-gaap_BusinessCombinationDescriptionAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Face amount or stated value per share of common stock.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_CommonStockParOrStatedValuePerShare
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentsAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents the maximum percentage allowed of the borrowing base allowed under a credit agreement.

+ References

No definition available.

+ Details

Name:	wttr_CollateralMaximumBorrowingBasePercent
Namespace Prefix:	wttr_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the percentage of an asset that serves as a part of a borrowing base under a credit agreement.

+ References

No definition available.

+ Details

Name:	wttr_CollateralPercentOfAsset
Namespace Prefix:	wttr_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The conversion rate of the stock converted in a transaction.

+ References

No definition available.

+ Details

Name:	wttr_ConversionOfStockConversionRate
Namespace Prefix:	wttr_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

The fixed charge coverage ratio as defined in the credit agreement

+ References

No definition available.

+ Details

Name:	wttr_FixedChargeCoverageRatio
Namespace Prefix:	wttr_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the additional borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

No definition available.

+ Details

Name:	wttr_LineOfCreditFacilityAdditionalBorrowingCapacity
Namespace Prefix:	wttr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represent the time period in wich the borrowing capacity can be increased.

+ References

No definition available.

+ Details

Name:	wttr_LineOfCreditFacilityAdditionalBorrowingCapacityTerm
Namespace Prefix:	wttr_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The base dollar amount used to determine if a distribution can be made.

+ References

No definition available.

+ Details

Name:	wttr_LineOfCreditFacilityBaseValueForDistributions
Namespace Prefix:	wttr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The lookback period used to determine if a distribution can be made.

+ References

No definition available.

+ Details

Name:	wttr_LineOfCreditFacilityLookBackPeriodForDistributions
Namespace Prefix:	wttr_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The percentage amount outstanding on the credit facility.

+ References

No definition available.

+ Details

Name:	wttr_LineOfCreditFacilityPercentageOutstanding
Namespace Prefix:	wttr_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_BusinessAcquisitionAxis=wttr_RockwaterEnergySolutionsIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_CommonClassAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=wttr_CommonClassOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_CommonClassBMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=wttr_SeniorSecuredCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_PrimeRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_BaseRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	wttr_BorrowingBaseAxis=wttr_EligibleBilledReceivablesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	wttr_BorrowingBaseAxis=wttr_EligibleUnbilledReceivablesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	wttr_BorrowingBaseAxis=wttr_EligibleInventoryMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	wttr_BorrowingBaseAxis=wttr_NetRecoveryPercentageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementScenarioAxis=wttr_DistributionsAllowedScenarioOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementScenarioAxis=wttr_DistributionsAllowedScenarioTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementScenarioAxis=wttr_CoverageRatioCriteriaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ShortTermDebtTypeAxis=us-gaap_LetterOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ShortTermDebtTypeAxis=us-gaap_BridgeLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=wttr_CommonClassTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

SUBSEQUENT EVENTS - (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	Jun. 30, 2018	Nov. 01, 2017	Sep. 30, 2017	Jul. 18, 2017	Dec. 31, 2016	Dec. 20, 2016
Rockwater
Completion of the Merger
Conversion rate per share				$ 0.7777
Class A common stock
Completion of the Merger
Par value			$ 0.01		$ 0.01
Class A-1 common stock
Completion of the Merger
Par value			0.01		0.01	$ 0.01
Class B common stock
Completion of the Merger
Par value			$ 0.01		$ 0.01
Subsequent Event
Completion of the Merger
Shares issued in Merger Agreement		37.3
Subsequent Event \| Senior secured credit facility
New Credit Agreement
Maximum borrowing capacity		$ 300.0
Additional borrowing capacity		$ 150.0
Time frame for increasing borrowing capacity		3 years
Percentage of borrwoing base allowed		35.00%
Margin (as a percent)		2.00%
Subsequent Event \| Senior secured credit facility \| Maximum
New Credit Agreement
Percentage of borrwoing base allowed		30.00%
Subsequent Event \| Senior secured credit facility \| LIBOR
New Credit Agreement
Margin (as a percent)	1.75%	1.00%
Subsequent Event \| Senior secured credit facility \| LIBOR \| Minimum
New Credit Agreement
Margin (as a percent)		1.50%
Subsequent Event \| Senior secured credit facility \| LIBOR \| Maximum
New Credit Agreement
Margin (as a percent)		2.00%
Subsequent Event \| Senior secured credit facility \| Federal Funds Rate
New Credit Agreement
Margin (as a percent)		0.50%
Subsequent Event \| Senior secured credit facility \| Base Rate Advances
New Credit Agreement
Margin (as a percent)	0.75%
Subsequent Event \| Senior secured credit facility \| Base Rate Advances \| Minimum
New Credit Agreement
Margin (as a percent)		0.50%
Subsequent Event \| Senior secured credit facility \| Base Rate Advances \| Maximum
New Credit Agreement
Margin (as a percent)		1.00%
Subsequent Event \| Senior secured credit facility \| Eligible billed receivables
New Credit Agreement
Borrowing base (as a percent)		85.00%
Subsequent Event \| Senior secured credit facility \| Eligible unbilled receivables
New Credit Agreement
Borrowing base (as a percent)		75.00%
Subsequent Event \| Senior secured credit facility \| Eligible inventory
New Credit Agreement
Borrowing base (as a percent)		70.00%
Subsequent Event \| Senior secured credit facility \| Net recovery percentage
New Credit Agreement
Borrowing base (as a percent)		85.00%
Subsequent Event \| Senior secured credit facility \| Criteria for distributions, scenario one
New Credit Agreement
Lookback period		30 days
Percentage outstanding		25.00%
Base amount		$ 37.5
Subsequent Event \| Senior secured credit facility \| Criteria for distributions, scenario two
New Credit Agreement
Lookback period		30 days
Percentage outstanding		20.00%
Base amount		$ 30.0
Fixed charge coverage ratio		1.00%
Subsequent Event \| Senior secured credit facility \| Coverage Ratio Criteria
New Credit Agreement
Lookback period		60 days
Percentage outstanding		10.00%
Base amount		$ 15.0
Fixed charge coverage ratio		100.00%
Subsequent Event \| Senior secured credit facility \| Letter of credit
New Credit Agreement
Maximum borrowing capacity		$ 40.0
Subsequent Event \| Senior secured credit facility \| Swingline loan
New Credit Agreement
Maximum borrowing capacity		$ 30.0
Subsequent Event \| Class A common stock \| Rockwater
Completion of the Merger
Par value		$ 0.01
Conversion rate per share		$ 0.7652
Shares issued in Merger Agreement		25.9
Subsequent Event \| Class A-1 common stock \| Rockwater
Completion of the Merger
Par value		$ 0.01
Subsequent Event \| Class A-2 common stock \| Rockwater
Completion of the Merger
Par value		$ 0.01
Shares issued in Merger Agreement		6.7
Subsequent Event \| Class B common stock \| Rockwater
Completion of the Merger
Par value		$ 0.01
Shares issued in Merger Agreement		4.4