Total Equity - Summary of Changes in Total Equity (Detail) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Change in Stockholders' Equity
Balance at the beginning of the period	$ 492,349
Balance at the beginning of the period (in shares)	29,466
Cumulative effect from change in accounting for stock compensation	$ 15
Walker & Dunlop net income	15,458	$ 21,313
Net income from noncontrolling interests	(125)
Stock-based compensation	3,618
Issuance of common stock in connection with equity compensation plans	3,291
Repurchase and retirement of common stock	(8,345)
Other	(9)
Balance at the end of the period	$ 506,252
Balance at the end of the period (in shares)	29,358
Common Stock
Change in Stockholders' Equity
Balance at the beginning of the period	$ 295
Balance at the beginning of the period (in shares)	29,466
Issuance of common stock in connection with equity compensation plans	$ 3
Issuance of common stock in connection with equity compensation plans (in shares)	257
Repurchase and retirement of common stock	$ (4)
Repurchase and retirement of common stock (in shares)	(365)
Balance at the end of the period	$ 294
Balance at the end of the period (in shares)	29,358
Additional Paid-In Capital
Change in Stockholders' Equity
Balance at the beginning of the period	$ 215,575
Cumulative effect from change in accounting for stock compensation	135
Stock-based compensation	3,618
Issuance of common stock in connection with equity compensation plans	3,288
Repurchase and retirement of common stock	(4,923)
Other	(9)
Balance at the end of the period	217,684
Retained Earnings
Change in Stockholders' Equity
Balance at the beginning of the period	272,030
Cumulative effect from change in accounting for stock compensation	(120)
Walker & Dunlop net income	15,458
Repurchase and retirement of common stock	(3,418)
Balance at the end of the period	283,950
Noncontrolling Interests
Change in Stockholders' Equity
Balance at the beginning of the period	4,449
Net income from noncontrolling interests	(125)
Balance at the end of the period	$ 4,324