| SEGMENT REPORTING AND VARIABLE INTEREST ENTITIES - Other Debt Segment Investments and Debt (Details 1) (USD $) In Thousands, unless otherwise specified | Mar. 31, 2015 | |||||||
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| Investments Carrying Value | $ 1,591,118us-gaap_Investments | [1] | ||||||
| Debt Face Amount | 1,286,504us-gaap_DebtInstrumentFaceAmount | |||||||
| Non-recourse [Member] | Subprime Mortgage Loans subject to Call Options [Member] | ||||||||
| Investments Face Amount | 406,217us-gaap_InvestmentOwnedBalancePrincipalAmount / us-gaap_InvestmentTypeAxis = nct_SubprimeMortgageLoansSubjectCallOptionsMember / us-gaap_StatementBusinessSegmentsAxis = nct_NonrecourseOtherSegmentMember | |||||||
| Investments Carrying Value | 406,217us-gaap_Investments / us-gaap_InvestmentTypeAxis = nct_SubprimeMortgageLoansSubjectCallOptionsMember / us-gaap_StatementBusinessSegmentsAxis = nct_NonrecourseOtherSegmentMember | |||||||
| Debt Face Amount | 406,217us-gaap_DebtInstrumentFaceAmount / us-gaap_InvestmentTypeAxis = nct_SubprimeMortgageLoansSubjectCallOptionsMember / us-gaap_StatementBusinessSegmentsAxis = nct_NonrecourseOtherSegmentMember | |||||||
| Debt Carrying Value | 406,217nct_DebtGrossSegmentDisclosure / us-gaap_InvestmentTypeAxis = nct_SubprimeMortgageLoansSubjectCallOptionsMember / us-gaap_StatementBusinessSegmentsAxis = nct_NonrecourseOtherSegmentMember | |||||||
| Other [Member] | Unlevered Real Estate Securities [Member] | ||||||||
| Investments Face Amount | 52,327us-gaap_InvestmentOwnedBalancePrincipalAmount / us-gaap_InvestmentTypeAxis = nct_RealEstateSecurities1Member / us-gaap_StatementBusinessSegmentsAxis = nct_OtherOtherSegmentMember | [2] | ||||||
| Investments Carrying Value | 12,252us-gaap_Investments / us-gaap_InvestmentTypeAxis = nct_RealEstateSecurities1Member / us-gaap_StatementBusinessSegmentsAxis = nct_OtherOtherSegmentMember | [2] | ||||||
| Other [Member] | Levered Real Estate Securities [Member] | ||||||||
| Investments Face Amount | 389,056us-gaap_InvestmentOwnedBalancePrincipalAmount / us-gaap_InvestmentTypeAxis = nct_RealEstateSecurities2Member / us-gaap_StatementBusinessSegmentsAxis = nct_OtherOtherSegmentMember | |||||||
| Investments Carrying Value | 409,037us-gaap_Investments / us-gaap_InvestmentTypeAxis = nct_RealEstateSecurities2Member / us-gaap_StatementBusinessSegmentsAxis = nct_OtherOtherSegmentMember | |||||||
| Debt Face Amount | 386,120us-gaap_DebtInstrumentFaceAmount / us-gaap_InvestmentTypeAxis = nct_RealEstateSecurities2Member / us-gaap_StatementBusinessSegmentsAxis = nct_OtherOtherSegmentMember | |||||||
| Debt Carrying Value | 386,120nct_DebtGrossSegmentDisclosure / us-gaap_InvestmentTypeAxis = nct_RealEstateSecurities2Member / us-gaap_StatementBusinessSegmentsAxis = nct_OtherOtherSegmentMember | |||||||
| Other [Member] | Other Investments [Member] | ||||||||
| Investments Carrying Value | 6,555us-gaap_Investments / us-gaap_InvestmentTypeAxis = us-gaap_OtherInvestmentsMember / us-gaap_StatementBusinessSegmentsAxis = nct_OtherOtherSegmentMember | |||||||
| Other [Member] | Residential Mortgage Loans [Member] | ||||||||
| Investments Face Amount | 931us-gaap_InvestmentOwnedBalancePrincipalAmount / us-gaap_InvestmentTypeAxis = us-gaap_ResidentialMortgageMember / us-gaap_StatementBusinessSegmentsAxis = nct_OtherOtherSegmentMember | |||||||
| Investments Carrying Value | 572us-gaap_Investments / us-gaap_InvestmentTypeAxis = us-gaap_ResidentialMortgageMember / us-gaap_StatementBusinessSegmentsAxis = nct_OtherOtherSegmentMember | |||||||
| Other Debt [Member] | ||||||||
| Investments Face Amount | 848,531us-gaap_InvestmentOwnedBalancePrincipalAmount / us-gaap_StatementBusinessSegmentsAxis = nct_OtherDebtSegmentMember | |||||||
| Investments Carrying Value | 834,633us-gaap_Investments / us-gaap_StatementBusinessSegmentsAxis = nct_OtherDebtSegmentMember | [1],[3] | ||||||
| Debt Face Amount | 792,337us-gaap_DebtInstrumentFaceAmount / us-gaap_StatementBusinessSegmentsAxis = nct_OtherDebtSegmentMember | |||||||
| Debt Carrying Value | $ 792,337nct_DebtGrossSegmentDisclosure / us-gaap_StatementBusinessSegmentsAxis = nct_OtherDebtSegmentMember | |||||||
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- Definition Amount of long-term debt before deduction of unamortized discount or premium. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt, with initial maturities beyond one year or the normal operating cycle, if longer. Prior to inter-segment elimination, as presented in segment reporting disclosures. No definition available. 
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- Definition Face (par) amount of debt instrument at time of issuance. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition For investments which are quantified by principal amount, the principle balance held at close of period. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Sum of the carrying amounts as of the balance sheet date of all investments. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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