TOTAL EQUITY - Summary of Changes in Total Equity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Change in Stockholders' Equity
Balances at the beginning of the period	$ 928,072	$ 907,192	$ 832,267	$ 814,981	$ 907,192	$ 814,981
Balance at the beginning of the period (in shares)		29,497			29,497
Cumulative effect adjustment for adoption of ASU 2016-02		$ (1,002)
Walker and Dunlop net income	42,196	44,218	41,112	36,861	$ 86,414	77,973
Net income (loss) from noncontrolling interests	(50)	(158)	(79)	(154)	(208)	(233)
Other comprehensive income (loss), net of tax	666	301	(53)	(127)
Stock-based compensation - equity classified	4,417	6,812	5,076	5,093
Issuance of common stock in connection with equity compensation plans	1	4,187	3,216	4,851
Repurchase and retirement of common stock	(1,756)	(24,159)	(57)	(21,400)
Cash dividends paid	(9,311)	(9,319)	(7,861)	(7,838)
Balances at the end of the period	$ 964,235	$ 928,072	$ 873,621	$ 832,267	$ 964,235	873,621
Balance at the end of the period (in shares)	29,964				29,964
Cash dividends paid per common share	$ 0.30	$ 0.30	$ 0.25	$ 0.25
Common Stock
Change in Stockholders' Equity
Balances at the beginning of the period	$ 300	$ 295	$ 301	$ 300	$ 295	$ 300
Balance at the beginning of the period (in shares)	29,973	29,497	30,148	30,016	29,497	30,016
Issuance of common stock in connection with equity compensation plans	$ 1	$ 9	$ 3	$ 5
Issuance of common stock in connection with equity compensation plans (in shares)	24	935	242	567
Repurchase and retirement of common stock	$ (1)	$ (4)		$ (4)
Repurchase and retirement of common stock (in shares)	(33)	(459)		(435)
Balances at the end of the period	$ 300	$ 300	$ 304	$ 301	$ 300	$ 304
Balance at the end of the period (in shares)	29,964	29,973	30,390	30,148	29,964	30,390
APIC
Change in Stockholders' Equity
Balances at the beginning of the period	$ 223,742	$ 235,152	$ 226,332	$ 229,080	$ 235,152	$ 229,080
Stock-based compensation - equity classified	4,417	6,812	5,076	5,093
Issuance of common stock in connection with equity compensation plans		4,178	3,213	4,846
Repurchase and retirement of common stock	(538)	(22,400)	(57)	(12,687)
Balances at the end of the period	227,621	223,742	234,564	226,332	227,621	234,564
AOCI
Change in Stockholders' Equity
Balances at the beginning of the period	226	(75)	(34)	93	(75)	93
Other comprehensive income (loss), net of tax	666	301	(53)	(127)
Balances at the end of the period	892	226	(87)	(34)	892	(87)
Retained Earnings
Change in Stockholders' Equity
Balances at the beginning of the period	698,894	666,752	600,257	579,943	666,752	579,943
Cumulative effect adjustment for adoption of ASU 2016-02		(1,002)
Walker and Dunlop net income	42,196	44,218	41,112	36,861
Repurchase and retirement of common stock	(1,217)	(1,755)		(8,709)
Cash dividends paid	(9,311)	(9,319)	(7,861)	(7,838)
Balances at the end of the period	730,562	698,894	633,508	600,257	730,562	633,508
Noncontrolling Interests
Change in Stockholders' Equity
Balances at the beginning of the period	4,910	5,068	5,411	5,565	5,068	5,565
Net income (loss) from noncontrolling interests	(50)	(158)	(79)	(154)
Balances at the end of the period	$ 4,860	$ 4,910	$ 5,332	$ 5,411	$ 4,860	$ 5,332