SEGMENTS (Detail) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2022 USD ($)	Jun. 30, 2022 USD ($)	Mar. 31, 2022 USD ($)	Sep. 30, 2021 USD ($)	Jun. 30, 2021 USD ($)	Mar. 31, 2021 USD ($)	Sep. 30, 2022 USD ($) segment	Sep. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)
Segments
Number of operating segments | segment							3
Revenues
Total revenues	$ 315,611			$ 346,290			$ 975,903	$ 851,989
Expenses
Personnel	157,059			170,181			469,608	407,817
Amortization and depreciation	59,846			53,498			177,101	148,879
Provision (benefit) for credit losses	1,218			1,266			(13,120)	(14,380)
Interest expense on corporate debt	9,306			1,766			22,123	5,291
Other operating expenses	33,991			24,836			102,400	62,171
Total expenses	261,420			251,547			758,112	609,778
Income from operations	54,191			94,743			217,791	242,211
Income tax expense	7,532			22,953			46,495	56,311
Net income before noncontrolling interests	46,659			71,790			171,296	185,900
Less: net income (loss) from noncontrolling interests	(174)	$ (179)	$ (679)	69			(1,032)	69
Walker and Dunlop net income	46,833	$ 54,286	$ 71,209	71,721	$ 56,058	$ 58,052	172,328	185,831
Net change in unrealized gains (losses) on pledged available-for-sale securities, net of taxes	(1,238)			159			(4,018)	769
Walker and Dunlop comprehensive income	45,595			71,880			168,310	186,600
Total assets	6,003,013			5,116,862			6,003,013	5,116,862	$ 5,205,989
Loan origination and debt brokerage fees, Net
Revenues
Total revenues	90,858			123,242			275,773	306,593
Fair value of expected net cash flows from servicing, net
Revenues
Total revenues	55,291			89,482			159,970	209,266
Servicing fees
Revenues
Total revenues	75,975			70,628			222,916	205,658
Property sales broker fees
Revenues
Total revenues	30,308			33,677			100,092	65,173
Investment management fees
Revenues
Total revenues	16,301			2,564			47,345	9,115
Net warehouse interest income
Revenues
Total revenues	3,980			5,583			14,021	14,768
Escrow earnings and other interest income
Revenues
Total revenues	18,129			2,032			26,683	5,972
Other revenue
Revenues
Total revenues	24,769			19,082			129,103	35,444
Operating Segments | Capital Markets
Revenues
Total revenues	183,374			251,041			555,640	594,237
Expenses
Personnel	125,980			139,890			363,619	332,519
Amortization and depreciation	952			17			1,762	556
Other operating expenses	6,063			4,628			16,757	11,628
Total expenses	132,995			144,535			382,138	344,703
Income from operations	50,379			106,506			173,502	249,534
Income tax expense	12,751			25,660			42,074	58,014
Net income before noncontrolling interests	37,628			80,846			131,428	191,520
Walker and Dunlop net income	37,628			80,846			131,428	191,520
Total assets	3,016,153			3,229,274			3,016,153	3,229,274
Operating Segments | Capital Markets | Loan origination and debt brokerage fees, Net
Revenues
Total revenues	89,752			121,133			273,660	302,011
Operating Segments | Capital Markets | Fair value of expected net cash flows from servicing, net
Revenues
Total revenues	55,291			89,482			159,970	209,266
Operating Segments | Capital Markets | Property sales broker fees
Revenues
Total revenues	30,308			33,677			100,092	65,173
Operating Segments | Capital Markets | Net warehouse interest income
Revenues
Total revenues	2,178			3,723			9,415	9,066
Operating Segments | Capital Markets | Other revenue
Revenues
Total revenues	5,845			3,026			12,503	8,721
Operating Segments | Servicing and Asset Management
Revenues
Total revenues	134,488			95,830			378,105	259,150
Expenses
Personnel	21,676			10,446			62,195	27,004
Amortization and depreciation	57,239			52,388			170,930	145,161
Provision (benefit) for credit losses	1,218			1,266			(13,120)	(14,380)
Other operating expenses	6,043			3,199			18,721	8,056
Total expenses	86,176			67,299			238,726	165,841
Income from operations	48,312			28,531			139,379	93,309
Income tax expense	12,110			7,040			33,799	21,693
Net income before noncontrolling interests	36,202			21,491			105,580	71,616
Less: net income (loss) from noncontrolling interests	(174)			69			(1,032)	69
Walker and Dunlop net income	36,376			21,422			106,612	71,547
Total assets	2,621,380			1,387,423			2,621,380	1,387,423
Operating Segments | Servicing and Asset Management | Loan origination and debt brokerage fees, Net
Revenues
Total revenues	1,106			2,109			2,113	4,582
Operating Segments | Servicing and Asset Management | Servicing fees
Revenues
Total revenues	75,975			70,628			222,916	205,658
Operating Segments | Servicing and Asset Management | Investment management fees
Revenues
Total revenues	16,301			2,564			47,345	9,115
Operating Segments | Servicing and Asset Management | Net warehouse interest income
Revenues
Total revenues	1,802			1,860			4,606	5,702
Operating Segments | Servicing and Asset Management | Escrow earnings and other interest income
Revenues
Total revenues	17,760			1,945			26,166	5,712
Operating Segments | Servicing and Asset Management | Other revenue
Revenues
Total revenues	21,544			16,724			74,959	28,381
Operating Segments | Corporate
Revenues
Total revenues	(2,251)			(581)			42,158	(1,398)
Expenses
Personnel	9,403			19,845			43,794	48,294
Amortization and depreciation	1,655			1,093			4,409	3,162
Interest expense on corporate debt	9,306			1,766			22,123	5,291
Other operating expenses	21,885			17,009			66,922	42,487
Total expenses	42,249			39,713			137,248	99,234
Income from operations	(44,500)			(40,294)			(95,090)	(100,632)
Income tax expense	(17,329)			(9,747)			(29,378)	(23,396)
Net income before noncontrolling interests	(27,171)			(30,547)			(65,712)	(77,236)
Walker and Dunlop net income	(27,171)			(30,547)			(65,712)	(77,236)
Total assets	365,480			500,165			365,480	500,165
Operating Segments | Corporate | Escrow earnings and other interest income
Revenues
Total revenues	369			87			517	260
Operating Segments | Corporate | Other revenue
Revenues
Total revenues	$ (2,620)			$ (668)			$ 41,641	$ (1,658)