Represents the expected filing duration that might be granted if Nasdaq accepts the plan.

No definition available.

Name:	ctrc_ExpectedFilingDurationThatMightBeGrantedIfNasdaqAcceptsPlan
Namespace Prefix:	ctrc_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The period within which the company should file its annual reports with the SEC as per the notice received.

+ References

No definition available.

+ Details

Name:	ctrc_PeriodWithinWhichCompanyShouldFileAnnualReports
Namespace Prefix:	ctrc_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of increase in undived ownership interest under the receivables purchase agreement.

+ References

No definition available.

+ Details

Name:	ctrc_ReceivablesPurchaseAgreementIncreaseInUndividedOwnershipInterestAmount
Namespace Prefix:	ctrc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents the maximum sale of undivided ownership interest under the receivables purchase agreement.

+ References

No definition available.

+ Details

Name:	ctrc_ReceivablesPurchaseAgreementMaximumSaleOfUndividedOwnershipInterest
Namespace Prefix:	ctrc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The amount of lumpsum cash payment made under the separation agreement relating to reimbursement for legal fees.

+ References

No definition available.

+ Details

Name:	ctrc_RelatedPartyTransactionsLumpsumCashPaymentOnSeparation
Namespace Prefix:	ctrc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The period for which full payment towards the cost of COBRA continuation coverage to be made.

+ References

No definition available.

+ Details

Name:	ctrc_RelatedPartyTransactionsPeriodOfInsuranceCoverageAfterSeparation
Namespace Prefix:	ctrc_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of the fee that accompanies borrowing money under the debt instrument.

+ References

+ Details

Name:	us-gaap_DebtInstrumentFeeAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ 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(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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

- 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

+ Details

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

- Definition

Number of shares for which recognition of compensation cost was accelerated.

+ References

No definition available.

+ Details

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

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

No definition available.

+ Details

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

- Details

Name:	us-gaap_TypeOfArrangementAxis=ctrc_RossSeparationAgreementMember
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_AwardTypeAxis=us-gaap_RestrictedStockUnitsRSUMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

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

Subsequent Events (Details) - USD ($)				12 Months Ended
Subsequent Events (Details) - USD ($)	Apr. 25, 2019	Jan. 04, 2019	Oct. 29, 2018	Dec. 31, 2018	Apr. 17, 2019	Apr. 16, 2019
Subsequent Event [Line Items]
Receivables Purchase Agreement, Maximum Sale Of Undivided Ownership Interest			$ 450,000,000
Period within which company should file annual reports				60 years
Expected filing duration that might be granted if Nasdaq accepts the plan				180 years
Ross Separation Agreement
Subsequent Event [Line Items]
Period of insurance coverage payment to be made		18 years
Ross Separation Agreement \| Subsequent Events
Subsequent Event [Line Items]
Lumpsum cash payment		$ 10,000
Ross Separation Agreement \| RSUs
Subsequent Event [Line Items]
Accelerated vesting		133,333
First Lien Credit Agreement \| Subsequent Events
Subsequent Event [Line Items]
Maximum borrowing capacity					$ 200,000,000	$ 150,000,000
Fee amount					1,500,000
Trade Receivables Securitization Facility Under R P A \| Subsequent Events
Subsequent Event [Line Items]
Maximum borrowing capacity					600,000,000	550,000,000
Receivables Purchase Agreement, Maximum Sale Of Undivided Ownership Interest	$ 600,000,000
Increase in undivided ownership interest	$ 150,000,000
Second Lien Credit Agreement \| Subsequent Events
Subsequent Event [Line Items]
Long-term Line of Credit					$ 845,000,000	$ 795,000,000