Percentage points added to the reference rate to compute the variable rate on the debt instrument.

No definition available.

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The reference rate for the variable rate of the debt instrument, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR.

+ References

No definition available.

+ Details

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

- Definition

Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28555-108399

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.17)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DeferredFinanceCostsNet
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

Date the credit facility terminates, in CCYY-MM-DD format.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityExpirationDate1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
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

+ Details

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

- Definition

The period of time for a line of credit extension option.

+ References

No definition available.

+ Details

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

- Definition

Temporary increase in maximum borrowing capacity under the credit facility.

+ References

No definition available.

+ Details

Name:	wd_LineOfCreditFacilityTemporaryIncreaseToMaximumBorrowingCapacity
Namespace Prefix:	wd_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

WAREHOUSE NOTES PAYABLE - Schedule of Debt (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Warehouse notes payable
Maximum Amount	$ 4,195,000	$ 4,195,000
Debt issuance costs	(622)	(622)
Outstanding Balance	1,630,268	1,630,268	$ 1,990,183
Agency Warehouse Facility
Warehouse notes payable
Maximum Amount	3,835,000	3,835,000
Outstanding Balance	1,434,728	1,434,728
Interim Warehouse Facility
Warehouse notes payable
Maximum Amount	360,000	360,000
Outstanding Balance	$ 196,162	$ 196,162
Agency Warehouse Facility #1 \| LIBOR
Warehouse notes payable
Reference rate for variable interest on the line of credit		30-day LIBOR
Basis points added to reference rate		1.40%
Agency Warehouse Facility #2 \| LIBOR
Warehouse notes payable
Reference rate for variable interest on the line of credit		30-day LIBOR
Basis points added to reference rate		1.40%
Agency Warehouse Facility #2 \| Agency Warehouse Facility
Warehouse notes payable
Term of facility extension option	1 year
Maturity date	Sep. 11, 2017
Agency Warehouse Facility #3 \| LIBOR
Warehouse notes payable
Reference rate for variable interest on the line of credit	30-day LIBOR	30-day LIBOR
Basis points added to reference rate	1.25%	1.25%
Agency Warehouse Facility #3 \| Agency Warehouse Facility
Warehouse notes payable
Maximum Amount	$ 480,000	$ 480,000
Maturity date	Apr. 30, 2018
Agency Warehouse Facility #3 \| Agency Warehouse Facility \| Temporary Commitment Increase Period Maturing July 2017
Warehouse notes payable
Temporary increase in maximum borrowing capacity	$ 400,000	$ 400,000
Maturity date	Jul. 30, 2017
Agency Warehouse Facility #4 \| LIBOR
Warehouse notes payable
Reference rate for variable interest on the line of credit		30-day LIBOR
Basis points added to reference rate		1.40%
Agency Warehouse Facility #5 \| LIBOR
Warehouse notes payable
Reference rate for variable interest on the line of credit		30-day LIBOR
Basis points added to reference rate		1.80%
Uncommitted Agency Warehouse Facility \| LIBOR
Warehouse notes payable
Reference rate for variable interest on the line of credit		30-day LIBOR
Basis points added to reference rate		1.15%
Interim Warehouse Facility #1 \| LIBOR
Warehouse notes payable
Reference rate for variable interest on the line of credit		30-day LIBOR
Basis points added to reference rate		1.90%
Interim Warehouse Facility #1 \| Interim Warehouse Facility
Warehouse notes payable
Maturity date	Apr. 30, 2018
Interim Warehouse Facility #2 \| LIBOR
Warehouse notes payable
Reference rate for variable interest on the line of credit		30-day LIBOR
Basis points added to reference rate		2.00%
Interim Warehouse Facility #3 \| LIBOR
Warehouse notes payable
Reference rate for variable interest on the line of credit		30-day LIBOR
Interim Warehouse Facility #3 \| LIBOR \| Minimum
Warehouse notes payable
Basis points added to reference rate		2.00%
Interim Warehouse Facility #3 \| LIBOR \| Maximum
Warehouse notes payable
Basis points added to reference rate		2.50%
Interim Warehouse Facility #3 \| Interim Warehouse Facility
Warehouse notes payable
Maturity date	May 19, 2018
Loans Held for Sale \| Agency Warehouse Facility #1 \| Agency Warehouse Facility
Warehouse notes payable
Maximum Amount	$ 425,000	$ 425,000
Outstanding Balance	224,431	224,431
Loans Held for Sale \| Agency Warehouse Facility #2 \| Agency Warehouse Facility
Warehouse notes payable
Maximum Amount	650,000	650,000
Outstanding Balance	470,003	470,003
Loans Held for Sale \| Agency Warehouse Facility #3 \| Agency Warehouse Facility
Warehouse notes payable
Maximum Amount	880,000	880,000
Outstanding Balance	387,932	387,932
Loans Held for Sale \| Agency Warehouse Facility #4 \| Agency Warehouse Facility
Warehouse notes payable
Maximum Amount	350,000	350,000
Outstanding Balance	238,902	238,902
Loans Held for Sale \| Agency Warehouse Facility #5 \| Agency Warehouse Facility
Warehouse notes payable
Maximum Amount	30,000	30,000
Outstanding Balance	20,348	20,348
Loans Held for Sale \| Uncommitted Agency Warehouse Facility \| Agency Warehouse Facility
Warehouse notes payable
Maximum Amount	1,500,000	1,500,000
Outstanding Balance	93,112	93,112
Loans Held for Sale \| Interim Warehouse Facilities #2 and #3 \| Interim Warehouse Facility
Warehouse notes payable
Outstanding Balance	88,600	88,600
Loans Held for Investment \| Interim Warehouse Facility #1 \| Interim Warehouse Facility
Warehouse notes payable
Maximum Amount	85,000	85,000
Outstanding Balance	43,440	43,440
Loans Held for Investment \| Interim Warehouse Facilities #2 and #3 \| Interim Warehouse Facility
Warehouse notes payable
Outstanding Balance	64,100	64,100
Loans Held for Investment \| Interim Warehouse Facility #2 \| Interim Warehouse Facility
Warehouse notes payable
Maximum Amount	200,000	200,000
Outstanding Balance	100,591	100,591
Loans Held for Investment \| Interim Warehouse Facility #3 \| Interim Warehouse Facility
Warehouse notes payable
Maximum Amount	75,000	75,000
Outstanding Balance	52,131	52,131
National Banks \| Agency Warehouse Facility
Warehouse notes payable
Maximum Amount	2,300,000	2,300,000
National Banks \| Interim Warehouse Facility
Warehouse notes payable
Maximum Amount	400,000	400,000
Fannie Mae \| Agency Warehouse Facility
Warehouse notes payable
Maximum Amount	$ 1,500,000	$ 1,500,000