Debt Instrument, Collateral, Percentage Of Non-Voting Capital Stock Of Foreign Subsidiaries

No definition available.

Name:	sem_DebtInstrumentCollateralPercentageOfNonVotingCapitalStockOfForeignSubsidiaries
Namespace Prefix:	sem_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Collateral, Percentage Of Voting Capital Stock Of Domestic Subsidiaries

+ References

No definition available.

+ Details

Name:	sem_DebtInstrumentCollateralPercentageOfVotingCapitalStockOfDomesticSubsidiaries
Namespace Prefix:	sem_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the leverage ratio as defined in the credit facility agreement

+ References

No definition available.

+ Details

Name:	sem_DebtInstrumentCovenantLeverageRatio
Namespace Prefix:	sem_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the premium for term loans prepayments.

+ References

No definition available.

+ Details

Name:	sem_DebtInstrumentCovenantPrepaymentPremiumRate
Namespace Prefix:	sem_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the percentage of net cash proceeds from all sales of assets or other dispositions by the entity or as a result of casualty or condemnation, subject to reinvestment provisions and other customary adjustments, required to be used for the prepayment of the debt instrument.

+ References

No definition available.

+ Details

Name:	sem_DebtInstrumentPercentageofNetProceedsfromAssetorOtherDispositionorCasualtyorCondemnationtobeUsedforPrepayment
Namespace Prefix:	sem_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the mandatory prepayment as a percentage of excess cash flows for any fiscal year if a specified leverage ratio is outside the threshold specified in the agreement.

+ References

No definition available.

+ Details

Name:	sem_DebtInstrumentPrepaymentasPercentageofExcessCashFlows
Namespace Prefix:	sem_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the mandatory prepayment as a percentage of the proceeds received from specified debt issuance.

+ References

No definition available.

+ Details

Name:	sem_DebtInstrumentPrepaymentasPercentageofProceedsofSpecifiedDebtIssuance
Namespace Prefix:	sem_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Line Of Credit Facility, Additional Borrowing Capacity

+ References

No definition available.

+ Details

Name:	sem_LineOfCreditFacilityAdditionalBorrowingCapacity
Namespace Prefix:	sem_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- 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

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

+ Details

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

- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentTerm
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_LineOfCreditFacilityLineItems
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

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_LineOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConsolidatedEntitiesAxis=sem_ConcentraIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

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

- Details

Name:	us-gaap_VariableRateAxis=sem_DebtInstrumentVariableRateBaseAdjustedLIBOFloorMember
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:	us-gaap_VariableRateAxis=sem_DebtInstrumentAlternateBaseRateFloorMember
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_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=sem_SecondLienCreditAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentRedemptionPeriodAxis=us-gaap_DebtInstrumentRedemptionPeriodOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentRedemptionPeriodAxis=us-gaap_DebtInstrumentRedemptionPeriodTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	sem_DebtInstrumentFinancialCovenantsRatiosAxis=sem_LeverageRatioGreaterThan4.25To1.00Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	sem_DebtInstrumentFinancialCovenantsRatiosAxis=sem_LessThanOrEqualTo4.25To1.00AndGreaterThan3.75To1.00Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	sem_DebtInstrumentFinancialCovenantsRatiosAxis=sem_LeverageRatioLessThanOrEqualTo3.75To1.00Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Long-Term Debt and Notes Payable - Concentra Credit Facilities (Details) - Credit facilities - Concentra Inc - USD ($)	Feb. 01, 2018	Jun. 01, 2015
Revolving facility
Line of Credit Facility [Line Items]
Additional borrowing capacity	$ 25,000,000.0
Maximum borrowing capacity		$ 50,000,000.0
Debt instrument term (in years)		5 years
Term loans
Line of Credit Facility [Line Items]
Additional borrowing capacity	$ 555,000,000.0
Adjusted LIBO \| Term loans
Line of Credit Facility [Line Items]
Interest rate margin (as a percent)	2.75%
Adjusted LIBO Rate floor \| Term loans
Line of Credit Facility [Line Items]
Interest rate margin (as a percent)	1.00%
Alternate Base Rate \| Term loans
Line of Credit Facility [Line Items]
Interest rate margin (as a percent)	1.75%
Alternate Base Rate floor \| Term loans
Line of Credit Facility [Line Items]
Interest rate margin (as a percent)	2.00%
Maximum \| Adjusted LIBO \| Revolving facility
Line of Credit Facility [Line Items]
Interest rate margin (as a percent)		3.00%
Maximum \| Alternate Base Rate \| Revolving facility
Line of Credit Facility [Line Items]
Interest rate margin (as a percent)		2.00%
Minimum \| Adjusted LIBO \| Revolving facility
Line of Credit Facility [Line Items]
Interest rate margin (as a percent)		2.75%
Minimum \| Alternate Base Rate \| Revolving facility
Line of Credit Facility [Line Items]
Interest rate margin (as a percent)		1.75%
Concentra second lien term agreement
Line of Credit Facility [Line Items]
Percentage of net cash proceeds received from non-ordinary course asset sales or other dispositions, or as a result of a casualty or condemnation to be used for prepayment of debt	100.00%
Percentage of net proceeds received from the issuance of debt obligations other than certain permitted debt obligations to be used for prepayment of debt	100.00%
Voting capital stock of domestic subsidiaries pledged (as a percent)	65.00%
Non-voting capital stock of foreign subsidiaries pledged (as a percent)	100.00%
Concentra second lien term agreement \| Term loans
Line of Credit Facility [Line Items]
Aggregate principal amount	$ 240,000,000.0
Concentra second lien term agreement \| On or prior to February 1, 2019 \| Term loans
Line of Credit Facility [Line Items]
Prepayment premium rate	2.00%
Concentra second lien term agreement \| On or prior to February 1, 2020 \| Term loans
Line of Credit Facility [Line Items]
Prepayment premium rate	1.00%
Concentra second lien term agreement \| Adjusted LIBO \| Term loans
Line of Credit Facility [Line Items]
Interest rate margin (as a percent)	6.50%
Concentra second lien term agreement \| Adjusted LIBO Rate floor \| Term loans
Line of Credit Facility [Line Items]
Interest rate margin (as a percent)	1.00%
Concentra second lien term agreement \| Alternate Base Rate \| Term loans
Line of Credit Facility [Line Items]
Interest rate margin (as a percent)	5.50%
Concentra second lien term agreement \| Alternate Base Rate floor \| Term loans
Line of Credit Facility [Line Items]
Interest rate margin (as a percent)	2.00%
Concentra second lien term agreement \| Leverage ratio greater than 4.25 to 1.00
Line of Credit Facility [Line Items]
Percentage of excess cash flow to be used for prepayment of debt	50.00%
Leverage ratio of financial maintenance covenant	4.25
Concentra second lien term agreement \| Less than or equal to 4.25 to 1.00 and greater than 3.75 to 1.00
Line of Credit Facility [Line Items]
Percentage of excess cash flow to be used for prepayment of debt	25.00%
Concentra second lien term agreement \| Leverage ratio less than or equal to 3.75 to 1.00
Line of Credit Facility [Line Items]
Leverage ratio of financial maintenance covenant	3.75
Concentra second lien term agreement \| Maximum \| Less than or equal to 4.25 to 1.00 and greater than 3.75 to 1.00
Line of Credit Facility [Line Items]
Leverage ratio of financial maintenance covenant	4.25
Concentra second lien term agreement \| Minimum \| Less than or equal to 4.25 to 1.00 and greater than 3.75 to 1.00
Line of Credit Facility [Line Items]
Leverage ratio of financial maintenance covenant	3.75