EARNINGS PER SHARE AND STOCKHOLDERS EQUITY - Basic and Diluted EPS (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Calculation of basic EPS
Walker and Dunlop net income	$ 71,209	$ 58,052
Less: dividends and undistributed earnings allocated to participating securities	2,172	1,967
Net income applicable to common stockholders	$ 69,037	$ 56,085
Basic weighted average shares outstanding	32,219	30,823
Basic EPS	$ 2.14	$ 1.82
Calculation of diluted EPS
Add: reallocation of dividends and undistributed earnings based on assumed conversion	$ 19	$ 20
Net income allocated to common stockholders	$ 69,056	$ 56,105
Add: weighted-average diluted non-participating securities	398	453
Weighted average diluted shares outstanding	32,617	31,276
Diluted EPS	$ 2.12	$ 1.79