TOTAL EQUITY - Summary of Changes in Total Equity (Detail) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Change in Stockholders' Equity
Balance at the beginning of the period			$ 615,074
Balance at the beginning of the period (in shares)			29,551
Walker & Dunlop net income	$ 34,567	$ 32,021	$ 77,788	$ 47,479
Net income from noncontrolling interests	(55)	$ 90	(216)	$ (35)
Stock-based compensation - equity classified			8,801
Issuance of common stock in connection with equity compensation plans			2,885
Repurchase and retirement of common stock			(17,590)
Other			9
Balance at the end of the period	$ 686,751		$ 686,751
Balance at the end of the period (in shares)	30,144		30,144
Common Stock
Change in Stockholders' Equity
Balance at the beginning of the period			$ 296
Balance at the beginning of the period (in shares)			29,551
Issuance of common stock in connection with equity compensation plans			$ 10
Issuance of common stock in connection with equity compensation plans (in shares)			1,033
Repurchase and retirement of common stock			$ (5)
Repurchase and retirement of common stock (in shares)			(440)
Balance at the end of the period	$ 301		$ 301
Balance at the end of the period (in shares)	30,144		30,144
Additional Paid-In Capital
Change in Stockholders' Equity
Balance at the beginning of the period			$ 228,889
Stock-based compensation - equity classified			8,801
Issuance of common stock in connection with equity compensation plans			2,875
Repurchase and retirement of common stock			(17,585)
Other			9
Balance at the end of the period	$ 222,989		222,989
Retained Earnings
Change in Stockholders' Equity
Balance at the beginning of the period			381,031
Walker & Dunlop net income			77,788
Balance at the end of the period	458,819		458,819
Noncontrolling Interests
Change in Stockholders' Equity
Balance at the beginning of the period			4,858
Net income from noncontrolling interests			(216)
Balance at the end of the period	$ 4,642		$ 4,642