Name:	us-gaap_AccountsNotesAndLoansReceivableLineItems
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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

This is the principal amount of loans (across all types of loans) that are overdue in payment by a set number of days.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 860
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (e)(4)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481326/860-20-50-4

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

Amount excluding accrued interest, of allowance for credit loss on financing receivable. Excludes net investment in lease.

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

Amount of writeoff of financing receivable, charged against allowance for credit loss.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
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-Topic 326
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-Name Accounting Standards Codification
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-Topic 310
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Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Amortized cost excluding accrued interest, before allowance for credit loss, of financing receivable. Excludes net investment in lease.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
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-Topic 326
-SubTopic 20
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-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
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Name:	us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amortized cost of financing receivable on nonaccrual status. Excludes net investment in lease.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
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-Subparagraph (a)
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-Name Regulation S-K (SK)
-Number 229
-Section 1405
-Paragraph (a)
-Subparagraph (3)
-Publisher SEC

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
-Section 1405
-Paragraph (a)
-Subparagraph (2)
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-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
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-Paragraph 7
-Subparagraph (a)
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Name:	us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount of unamortized loan commitment, origination, and other costs (fees) on financing receivable recognized as adjustment to yield. Excludes financing receivable covered under loss sharing agreement.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
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-Topic 310
-SubTopic 20
-Name Accounting Standards Codification
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-Paragraph 1
-Publisher FASB
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-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-SubTopic 20
-Topic 310
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481569/310-20-50-3

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

This is the result of the principal amount outstanding of total loans managed or securitized less securitized loans and loans that are in the process of being securitized.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Subparagraph (a)
-Paragraph 4
-SubTopic 20
-Topic 860
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-URI https://asc.fasb.org//1943274/2147481326/860-20-50-4

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

Amount of cash inflow from sale of loan held for investment.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
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Name:	us-gaap_ProceedsFromSaleOfLoansHeldForInvestment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

The amount of specific reserve for financial receivables.

No definition available.

Name:	wd_FinancingReceivableSpecificReserve
Namespace Prefix:	wd_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Maximum period for loans held-for-investment, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

Name:	wd_LoansHeldForInvestmentMaximumTerm
Namespace Prefix:	wd_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Number of loans that are considered delinquent (past due) at the end of the period.

No definition available.

Name:	wd_NumberOfDelinquentLoans
Namespace Prefix:	wd_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

The number of real estate loans held for investment.

No definition available.

Name:	wd_NumberOfLoansHeldForInvestment
Namespace Prefix:	wd_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

The number of loans on nonaccrual status at the end of the period.

No definition available.