Balance relating loan portfolio held in bank trust account.

No definition available.

Name:	ck0001448038_BalanceRelatingLoanPortfolioHeldInBankTrustAccount
Namespace Prefix:	ck0001448038_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Balance relating to loan portfolio held in bank trust account, disbursement date to partnership.

+ References

No definition available.

+ Details

Name:	ck0001448038_BalanceRelatingToLoanPortfolioHeldInBankTrustAccountDisbursementDateToPartnership
Namespace Prefix:	ck0001448038_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Loans details.

+ References

No definition available.

+ Details

Name:	ck0001448038_LoansDetailsLineItems
Namespace Prefix:	ck0001448038_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Term, in years, of the typical amortization used on loans made.

+ References

No definition available.

+ Details

Name:	ck0001448038_LoansReceivableAmortizationTerm
Namespace Prefix:	ck0001448038_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Largest principal balance on a single loan in the secured loan portfolio.

+ References

No definition available.

+ Details

Name:	ck0001448038_LoansReceivableLargestLoan
Namespace Prefix:	ck0001448038_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Loans receivable maturity date.

+ References

No definition available.

+ Details

Name:	ck0001448038_LoansReceivableMaturityDate
Namespace Prefix:	ck0001448038_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Loans receivable number of loans matured.

+ References

No definition available.

+ Details

Name:	ck0001448038_LoansReceivableNumberOfLoansMatured
Namespace Prefix:	ck0001448038_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Loans receivable number of principal and interest loans.

+ References

No definition available.

+ Details

Name:	ck0001448038_LoansReceivableNumberOfPrincipalAndInterestLoans
Namespace Prefix:	ck0001448038_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the loans receivable, percent of aggregate principal.

+ References

No definition available.

+ Details

Name:	ck0001448038_LoansReceivablePercentOfAggregatePrincipal
Namespace Prefix:	ck0001448038_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Loans receivable, percent of assets.

+ References

No definition available.

+ Details

Name:	ck0001448038_LoansReceivablePercentOfAssets
Namespace Prefix:	ck0001448038_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Loans receivable, remaining term.

+ References

No definition available.

+ Details

Name:	ck0001448038_LoansReceivableRemainingTerm
Namespace Prefix:	ck0001448038_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Term, in years, of the typical loan made.

+ References

No definition available.

+ Details

Name:	ck0001448038_LoansReceivableTerm
Namespace Prefix:	ck0001448038_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Loans receivable, yield of loan acquired.

+ References

No definition available.

+ Details

Name:	ck0001448038_LoansReceivableYieldOfLoanAcquired
Namespace Prefix:	ck0001448038_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Mortgage loans on real estate principal renewed.

+ References

No definition available.

+ Details

Name:	ck0001448038_MortgageLoansOnRealEstatePrincipalRenewed
Namespace Prefix:	ck0001448038_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Mortgage loans on real estate renewed number of loans.

+ References

No definition available.

+ Details

Name:	ck0001448038_MortgageLoansOnRealEstateRenewedNumberOfLoans
Namespace Prefix:	ck0001448038_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Percent of total secured loans with a similar property type.

+ References

No definition available.

+ Details

Name:	ck0001448038_PercentOfLoansReceivable
Namespace Prefix:	ck0001448038_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of loan portfolio limited for funding of construction loans.

+ References

No definition available.

+ Details

Name:	ck0001448038_PercentageOfLoanPortfolioLimitedForFundingOfConstructionLoans
Namespace Prefix:	ck0001448038_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of loan portfolio limited for funding of rehabilitation loans.

+ References

No definition available.

+ Details

Name:	ck0001448038_PercentageOfLoanPortfolioLimitedForFundingOfRehabilitationLoans
Namespace Prefix:	ck0001448038_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

This element represents the aggregate of the assets reported on the balance sheet at period end measured at fair value on a nonrecurring basis by the entity. This element is intended to be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements.

+ References

No definition available.

+ Details

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

- Definition

Number of financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953676-111524

+ Details

Name:	us-gaap_FinancingReceivableModificationsNumberOfContracts2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Recorded investment in financing receivables that are 90 days or more past due and still accruing.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5111-111524

+ Details

Name:	us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Recorded investment in financing receivables that are on nonaccrual status as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5111-111524

+ Details

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

- Definition

Aggregation of the liabilities reported on the balance sheet measured at fair value on a nonrecurring basis by the entity.

+ References

No definition available.

+ Details

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

- Definition

The balance represents the amount of loans that are secured by real estate mortgages, offset by the reserve to cover probable credit losses on the loan portfolio.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.1(c))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

+ Details

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

- Definition

Indicates the number of mortgages under each classification.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 948
-SubTopic 310
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29.3)
-URI http://asc.fasb.org/extlink&oid=6589523&loc=d3e617274-123014

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 10
-Section S99
-Paragraph 6
-Subparagraph (SX 210.5-04.(c) Schedule IV)
-URI http://asc.fasb.org/extlink&oid=27047687&loc=d3e5864-122674

+ Details

Name:	us-gaap_MortgageLoansOnRealEstateNumberOfLoans
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_MortgageLoansOnRealEstateDescriptionLoanCategoryAxis=us-gaap_ConstructionLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MortgageLoansOnRealEstateDescriptionLoanCategoryAxis=ck0001448038_RehabilitationLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=ck0001448038_ImpairedLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablesPeriodPastDueAxis=ck0001448038_FinancingReceivablesOneToThreeThirtyFourDaysPastDueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MortgageLoansOnRealEstateLoanTypeAxis=ck0001448038_FiveYearsOrLessTermLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MortgageLoansOnRealEstateLoanTypeAxis=ck0001448038_InterestOnlyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MortgageLoansOnRealEstateLoanTypeAxis=ck0001448038_LargestLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=ck0001448038_FiledNoticeOfSaleMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
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Period Type:

Loans - Additional Information (Details)	3 Months Ended	12 Months Ended
Loans - Additional Information (Details)	Mar. 31, 2018 USD ($) MortgageLoan Loan	Dec. 31, 2017 USD ($) MortgageLoan Loan	Mar. 31, 2017 USD ($)
Loans (Details) [Line Items]
Loans Receivable, Term	5 years
Mortgage Loans on Real Estate, Number of Loans \| MortgageLoan	93	93
Loans Receivable, Number of Principal and Interest Loans \| Loan	69
Loans Receivable, Amortization Term	30 years
Mortgage Loans on Real Estate Renewed, Number of Loans \| MortgageLoan	4
Loans - principal renewed (in Dollars)	$ 1,324,473
Loans Receivable Largest Loan (in Dollars)	$ 3,200,000	$ 3,239,124
Loans Receivable, Percent	100.00%	100.00%
Balance relating to loan portfolio held in bank trust account	$ 50,209
Mortgage Loans on Real Estate, Number of Loans \| MortgageLoan	1
Financing receivable, recorded investment, 90 days past due and still accruing	$ 0	$ 0
Financing Receivable, Modifications, Number of Contracts \| Loan	0	0
Loans - principal (in Dollars)	$ 57,865,391	$ 54,768,689
Percentage of loan portfolio limited for funding of construction loans	10.00%
Percentage of loan portfolio limited for funding of rehabilitation loans	15.00%
Assets measured at fair value on non-recurring basis	$ 0		$ 0
Liabilities measured at fair value on non-recurring basis	0		$ 0
Construction Loans [Member]
Loans (Details) [Line Items]
Loans - principal (in Dollars)	0
Rehabilitation Loans [Member]
Loans (Details) [Line Items]
Loans - principal (in Dollars)	$ 0
Impaired Loans [Member]
Loans (Details) [Line Items]
Mortgage Loans on Real Estate, Number of Loans \| MortgageLoan	1	1
Impaired Loans [Member] \| Past Maturity 1 to 334 Days [Member]
Loans (Details) [Line Items]
Mortgage Loans on Real Estate, Number of Loans \| MortgageLoan	1
Financing Receivable, Recorded Investment, Nonaccrual Status (in Dollars)	$ 139,162
Five Years Or Less Term Loans [Member]
Loans (Details) [Line Items]
Mortgage Loans on Real Estate, Number of Loans \| MortgageLoan	87
Loans Receivable, Percent of Aggregate Principal	98.00%
Interest Only [Member]
Loans (Details) [Line Items]
Loans Receivable, Percent of Aggregate Principal	67.00%
Largest Loan [Member]
Loans (Details) [Line Items]
Loans Receivable, Percent	5.50%
Loans Receivable, Percent of Assets	4.70%
Loans Receivable, Yield of Loan Acquired	8.75%
Loans Receivable Maturity Date	Nov. 01, 2018
Largest Loan [Member] \| Filed Notice Of Sale [Member]
Loans (Details) [Line Items]
Mortgage Loans on Real Estate, Number of Loans \| MortgageLoan	1
Minimum [Member]
Loans (Details) [Line Items]
Loans Receivable, Remaining Term	5 years
Maximum [Member]
Loans (Details) [Line Items]
Balance relating to loan portfolio held in bank trust account, disbursement date to partnership	Apr. 13, 2018