Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2019	Jan. 31, 2020	Jun. 30, 2019
Document And Entity Information
Document Type	10-K
Document Annual Report	true
Document Transition Report	false
Document Period End Date	Dec. 31, 2019
Entity File Number	001-35000
Entity Registrant Name	Walker & Dunlop, Inc.
Entity Incorporation, State or Country Code	MD
Entity Tax Identification Number	80-0629925
Entity Address, Address Line One	7501 Wisconsin Avenue
Entity Address, Address Line Two	Suite 1200E
Entity Address, City or Town	Bethesda
Entity Address, State or Province	MD
Entity Address, Postal Zip Code	20814
City Area Code	301
Local Phone Number	215-5500
Title of 12(b) Security	Common Stock, $0.01 Par Value Per Share
Trading Symbol	WD
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		30,948,270
Entity Public Float			$ 1.0
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Entity Central Index Key	0001497770
Amendment Flag	false