EARNINGS PER SHARE - Basic and Diluted EPS (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Calculation of basic EPS
Walker and Dunlop net income	$ 47,829	$ 44,218
Less: dividends and undistributed earnings allocated to participating securities	1,510	1,509
Net income applicable to common stockholders	$ 46,319	$ 42,709
Basic weighted average shares outstanding	30,226	29,680
Basic EPS	$ 1.53	$ 1.44
Calculation of diluted EPS
Add: reallocation of dividends and undistributed earnings based on assumed conversion	$ 34	$ 38
Net income allocated to common stockholders	$ 46,353	$ 42,747
Add: weighted-average diluted non-participating securities	934	1,004
Weighted average diluted shares outstanding	31,160	30,684
Diluted EPS	$ 1.49	$ 1.39