Guaranty Obligation and Allowance for Risk-Sharing Obligations - Additional Information (Detail)	3 Months Ended
Mar. 31, 2016
GUARANTY OBLIGATION AND ALLOWANCE FOR RISK-SHARING OBLIGATIONS
Maximum delinquency period of loans at which initial loss recognition occurs	60 days

Maximum number of days a loan is delinquent before a loss is typically recognized in the financial statements.

No definition available.

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