TOTAL EQUITY - Summary of Changes in Total Equity (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Change in Stockholders' Equity
Balances at the beginning of the period	$ 814,981
Balance at the beginning of the period (in shares)	30,016
Walker and Dunlop net income	$ 36,861	$ 43,221
Other comprehensive income (loss), net of tax	(127)
Net income (loss) from noncontrolling interests	(154)	$ (161)
Stock-based compensation - equity classified	5,093
Issuance of common stock in connection with equity compensation plans	4,851
Repurchase and retirement of common stock	(21,400)
Cash dividends paid	(7,838)
Balances at the end of the period	$ 832,267
Balance at the end of the period (in shares)	30,148
Common Stock
Change in Stockholders' Equity
Balances at the beginning of the period	$ 300
Balance at the beginning of the period (in shares)	30,016
Issuance of common stock in connection with equity compensation plans	$ 5
Issuance of common stock in connection with equity compensation plans (in shares)	567
Repurchase and retirement of common stock	$ (4)
Repurchase and retirement of common stock (in shares)	(435)
Balances at the end of the period	$ 301
Balance at the end of the period (in shares)	30,148
Additional Paid-In Capital
Change in Stockholders' Equity
Balances at the beginning of the period	$ 229,080
Stock-based compensation - equity classified	5,093
Issuance of common stock in connection with equity compensation plans	4,846
Repurchase and retirement of common stock	(12,687)
Balances at the end of the period	226,332
AOCI
Change in Stockholders' Equity
Balances at the beginning of the period	93
Other comprehensive income (loss), net of tax	(127)
Balances at the end of the period	(34)
Retained Earnings
Change in Stockholders' Equity
Balances at the beginning of the period	579,943
Walker and Dunlop net income	36,861
Repurchase and retirement of common stock	(8,709)
Cash dividends paid	(7,838)
Balances at the end of the period	600,257
Noncontrolling Interests
Change in Stockholders' Equity
Balances at the beginning of the period	5,565
Net income (loss) from noncontrolling interests	(154)
Balances at the end of the period	$ 5,411