EARNINGS PER SHARE AND STOCKHOLDERS EQUITY - Basic and Diluted EPS (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021
Calculation of basic EPS
Walker and Dunlop net income	$ 46,833	$ 54,286	$ 71,209	$ 71,721	$ 56,058	$ 58,052	$ 172,328	$ 185,831
Less: dividends and undistributed earnings allocated to participating securities	1,296			2,364			4,984	6,163
Net income applicable to common stockholders	$ 45,537			$ 69,357			$ 167,344	$ 179,668
Basic weighted average shares outstanding	32,290			31,064			32,300	30,969
Basic EPS	$ 1.41			$ 2.23			$ 5.18	$ 5.80
Calculation of diluted EPS
Add: reallocation of dividends and undistributed earnings based on assumed conversion	$ 7			$ 23			$ 34	$ 57
Net income allocated to common stockholders	$ 45,544			$ 69,380			$ 167,378	$ 179,725
Add: weighted-average diluted non-participating securities	330			395			345	398
Weighted average diluted shares outstanding	32,620			31,459			32,645	31,367
Diluted EPS	$ 1.40			$ 2.21			$ 5.13	$ 5.73
Shares outstanding excluded from computation of earnings per share	218						111