TOTAL EQUITY - Summary of Changes in Total Equity (Detail) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 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	$ 43,221	$ 15,458
Net income from noncontrolling interests	(161)	$ (125)
Stock-based compensation - equity classified	4,681
Issuance of common stock in connection with equity compensation plans	2,884
Repurchase and retirement of common stock	(17,541)
Balance at the end of the period	$ 648,158
Balance at the end of the period (in shares)	30,095
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	$ 9
Issuance of common stock in connection with equity compensation plans (in shares)	983
Repurchase and retirement of common stock	$ (4)
Repurchase and retirement of common stock (in shares)	(439)
Balance at the end of the period	$ 301
Balance at the end of the period (in shares)	30,095
Additional Paid-In Capital
Change in Stockholders' Equity
Balance at the beginning of the period	$ 228,889
Stock-based compensation - equity classified	4,681
Issuance of common stock in connection with equity compensation plans	2,875
Repurchase and retirement of common stock	(17,537)
Balance at the end of the period	218,908
Retained Earnings
Change in Stockholders' Equity
Balance at the beginning of the period	381,031
Walker & Dunlop net income	43,221
Balance at the end of the period	424,252
Noncontrolling Interests
Change in Stockholders' Equity
Balance at the beginning of the period	4,858
Net income from noncontrolling interests	(161)
Balance at the end of the period	$ 4,697