TOTAL EQUITY - Summary of Changes in Total Equity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Change in Stockholders' Equity
Balances at the beginning of the period	$ 1,042,285	$ 907,192
Balance at the beginning of the period (in shares)	30,035
Walker and Dunlop net income	$ 47,829	44,218
Net income (loss) from noncontrolling interests	(224)	(158)
Contributions from noncontrolling interests	675
Other comprehensive income (loss), net of tax	(1,918)	301
Stock-based compensation - equity classified	5,061	6,812
Issuance of common stock in connection with equity compensation plans	11,369	4,187
Repurchase and retirement of common stock	(26,737)	(24,159)
Cash dividends paid	(11,347)	(9,319)
Balances at the end of the period	$ 1,043,315	$ 928,072
Balance at the end of the period (in shares)	30,330
Cash dividends paid per common share	$ 0.36	$ 0.30
ASU 2016-02
Change in Stockholders' Equity
Cumulative effect adjustment for adoption of ASU, net of tax		$ (1,002)
ASU 2016-13
Change in Stockholders' Equity
Cumulative effect adjustment for adoption of ASU, net of tax	$ (23,678)
Common Stock
Change in Stockholders' Equity
Balances at the beginning of the period	$ 300	$ 295
Balance at the beginning of the period (in shares)	30,035	29,497
Issuance of common stock in connection with equity compensation plans	$ 7	$ 9
Issuance of common stock in connection with equity compensation plans (in shares)	675	935
Repurchase and retirement of common stock	$ (4)	$ (4)
Repurchase and retirement of common stock (in shares)	(380)	(459)
Balances at the end of the period	$ 303	$ 300
Balance at the end of the period (in shares)	30,330	29,973
APIC
Change in Stockholders' Equity
Balances at the beginning of the period	$ 237,877	$ 235,152
Stock-based compensation - equity classified	5,061	6,812
Issuance of common stock in connection with equity compensation plans	11,362	4,178
Repurchase and retirement of common stock	(18,293)	(22,400)
Balances at the end of the period	236,007	223,742
AOCI
Change in Stockholders' Equity
Balances at the beginning of the period	737	(75)
Other comprehensive income (loss), net of tax	(1,918)	301
Balances at the end of the period	(1,181)	226
Retained Earnings
Change in Stockholders' Equity
Balances at the beginning of the period	796,775	666,752
Walker and Dunlop net income	47,829	44,218
Repurchase and retirement of common stock	(8,440)	(1,755)
Cash dividends paid	(11,347)	(9,319)
Balances at the end of the period	801,139	698,894
Retained Earnings | ASU 2016-02
Change in Stockholders' Equity
Cumulative effect adjustment for adoption of ASU, net of tax		(1,002)
Retained Earnings | ASU 2016-13
Change in Stockholders' Equity
Cumulative effect adjustment for adoption of ASU, net of tax	(23,678)
Noncontrolling Interests
Change in Stockholders' Equity
Balances at the beginning of the period	6,596	5,068
Net income (loss) from noncontrolling interests	(224)	(158)
Contributions from noncontrolling interests	675
Balances at the end of the period	$ 7,047	$ 4,910