QUARTERLY RESULTS (UNAUDITED) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Unaudited selected financial data and operating information
Gains from mortgage banking activities	$ 117,779	$ 100,630	$ 102,453	$ 46,323	$ 76,986	$ 70,810	$ 69,950	$ 72,720	$ 367,185	$ 290,466	$ 221,983
Servicing fees	39,370	37,134	32,771	31,649	30,530	29,328	28,058	26,841	140,924	114,757	98,414
Total revenues	178,391	154,786	147,858	94,241	121,365	120,786	113,926	112,121	575,276	468,198	360,772
Personnel	73,126	64,377	55,758	34,230	49,224	49,328	45,993	40,045	227,491	184,590	149,374
Amortization and depreciation	30,603	29,244	26,425	25,155	24,385	25,644	23,470	24,674	111,427	98,173	80,138
Total expenses	117,210	106,074	96,152	70,059	87,493	87,340	81,284	76,715	389,495	332,832	276,860
Operating income	61,181	48,712	51,706	24,182	33,872	33,446	32,642	35,406	185,781	135,366	83,912
Walker & Dunlop net income	$ 36,790	$ 29,628	$ 32,021	$ 15,458	$ 20,411	$ 20,251	$ 20,153	$ 21,313	$ 113,897	$ 82,128	$ 51,422
Diluted earnings per share	$ 1.16	$ 0.96	$ 1.05	$ 0.50	$ 0.67	$ 0.66	$ 0.67	$ 0.66	$ 3.65	$ 2.65	$ 1.58
Total originations	$ 6,260,898	$ 5,032,238	$ 5,389,276	$ 2,615,700	$ 4,686,283	$ 4,936,762	$ 3,787,305	$ 4,348,398
Servicing portfolio	$ 63,081,154	$ 59,121,989	$ 57,321,824	$ 51,040,752	$ 50,212,264	$ 47,794,561	$ 47,713,739	$ 46,066,660	$ 63,081,154	$ 50,212,264	$ 44,031,890