SEGMENTS (Detail) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2022 USD ($)	Mar. 31, 2022 USD ($)	Jun. 30, 2021 USD ($)	Mar. 31, 2021 USD ($)	Jun. 30, 2022 USD ($) segment	Jun. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)
Segments
Number of operating segments | segment					3
Revenues
Total revenues	$ 340,848		$ 281,411		$ 660,292	$ 505,699
Expenses
Personnel	168,368		141,421		312,549	237,636
Amortization and depreciation	61,103		48,510		117,255	95,381
Provision (benefit) for credit losses	(4,840)		(4,326)		(14,338)	(15,646)
Interest expense on corporate debt	6,412		1,760		12,817	3,525
Other operating expenses	36,195		19,748		68,409	37,335
Total expenses	267,238		207,113		496,692	358,231
Income from operations	73,610		74,298		163,600	147,468
Income tax expense	19,503		18,240		38,963	33,358
Net income before noncontrolling interests	54,107		56,058		124,637	114,110
Less: net income (loss) from noncontrolling interests	(179)	$ (679)			(858)
Walker and Dunlop net income	54,286	$ 71,209	56,058	$ 58,052	125,495	114,110
Total assets	4,534,772		3,943,121		4,534,772	3,943,121	$ 5,205,989
Loan origination and debt brokerage fees, Net
Revenues
Total revenues	102,605		107,472		184,915	183,351
Fair value of expected net cash flows from servicing, net
Revenues
Total revenues	51,949		61,849		104,679	119,784
Servicing fees
Revenues
Total revenues	74,260		69,052		146,941	135,030
Property sales broker fees
Revenues
Total revenues	46,386		22,454		69,784	31,496
Investment management fees
Revenues
Total revenues	10,282		3,815		22,930	6,551
Net warehouse interest income
Revenues
Total revenues	5,268		4,630		10,041	9,185
Escrow earnings and other interest income
Revenues
Total revenues	6,751		1,823		8,554	3,940
Other revenue
Revenues
Total revenues	43,347		10,316		112,448	16,362
Operating Segments | Capital Markets
Revenues
Total revenues	208,022		195,905		372,266	343,196
Expenses
Personnel	138,913		119,994		237,639	192,629
Amortization and depreciation	810		18		810	539
Other operating expenses	4,583		3,598		10,694	7,000
Total expenses	144,306		123,610		249,143	200,168
Income from operations	63,716		72,295		123,123	143,028
Income tax expense	16,476		17,739		29,323	32,354
Net income before noncontrolling interests	47,240		54,556		93,800	110,674
Walker and Dunlop net income	47,240		54,556		93,800	110,674
Total assets	1,611,951		2,070,549		1,611,951	2,070,549
Operating Segments | Capital Markets | Loan origination and debt brokerage fees, Net
Revenues
Total revenues	102,085		105,583		183,908	180,878
Operating Segments | Capital Markets | Fair value of expected net cash flows from servicing, net
Revenues
Total revenues	51,949		61,849		104,679	119,784
Operating Segments | Capital Markets | Property sales broker fees
Revenues
Total revenues	46,386		22,454		69,784	31,496
Operating Segments | Capital Markets | Net warehouse interest income
Revenues
Total revenues	3,707		2,884		7,237	5,343
Operating Segments | Capital Markets | Other revenue
Revenues
Total revenues	3,895		3,135		6,658	5,695
Operating Segments | Servicing and Asset Management
Revenues
Total revenues	132,551		85,155		243,617	163,320
Expenses
Personnel	21,881		9,447		40,519	16,558
Amortization and depreciation	58,760		47,395		113,691	92,773
Provision (benefit) for credit losses	(4,840)		(4,326)		(14,338)	(15,646)
Other operating expenses	6,559		2,604		12,678	4,857
Total expenses	82,360		55,120		152,550	98,542
Income from operations	50,191		30,035		91,067	64,778
Income tax expense	12,850		7,475		21,689	14,653
Net income before noncontrolling interests	37,341		22,560		69,378	50,125
Less: net income (loss) from noncontrolling interests	(179)				(858)
Walker and Dunlop net income	37,520		22,560		70,236	50,125
Total assets	2,607,990		1,404,895		2,607,990	1,404,895
Operating Segments | Servicing and Asset Management | Loan origination and debt brokerage fees, Net
Revenues
Total revenues	520		1,889		1,007	2,473
Operating Segments | Servicing and Asset Management | Servicing fees
Revenues
Total revenues	74,260		69,052		146,941	135,030
Operating Segments | Servicing and Asset Management | Investment management fees
Revenues
Total revenues	10,282		3,815		22,930	6,551
Operating Segments | Servicing and Asset Management | Net warehouse interest income
Revenues
Total revenues	1,561		1,746		2,804	3,842
Operating Segments | Servicing and Asset Management | Escrow earnings and other interest income
Revenues
Total revenues	6,648		1,768		8,406	3,767
Operating Segments | Servicing and Asset Management | Other revenue
Revenues
Total revenues	39,280		6,885		61,529	11,657
Operating Segments | Corporate
Revenues
Total revenues	275		351		44,409	(817)
Expenses
Personnel	7,574		11,980		34,391	28,449
Amortization and depreciation	1,533		1,097		2,754	2,069
Interest expense on corporate debt	6,412		1,760		12,817	3,525
Other operating expenses	25,053		13,546		45,037	25,478
Total expenses	40,572		28,383		94,999	59,521
Income from operations	(40,297)		(28,032)		(50,590)	(60,338)
Income tax expense	(9,823)		(6,974)		(12,049)	(13,649)
Net income before noncontrolling interests	(30,474)		(21,058)		(38,541)	(46,689)
Walker and Dunlop net income	(30,474)		(21,058)		(38,541)	(46,689)
Total assets	314,831		467,677		314,831	467,677
Operating Segments | Corporate | Escrow earnings and other interest income
Revenues
Total revenues	103		55		148	173
Operating Segments | Corporate | Other revenue
Revenues
Total revenues	$ 172		$ 296		$ 44,261	$ (990)