Basis of Presentation and Significant Accounting Policies - Additional Information (Details)	1 Months Ended	3 Months Ended		5 Months Ended	6 Months Ended
	Feb. 07, 2025 USD ($) Segment	Jun. 30, 2025 USD ($)	Jun. 30, 2024 USD ($)	Jun. 30, 2025 USD ($) Segment	Jun. 30, 2025 USD ($) $ / shares	Jun. 30, 2024 USD ($)	Dec. 31, 2024 USD ($)
Basis of presentation and significant accounting policies [Line Items]
Number of reportable segment | Segment	0			1
Number of operating segment | Segment				1
Segment Reporting, CODM, Individual Title and Position or Group Name [Extensible Enumeration]					srt:ChiefExecutiveOfficerMember
Segment Reporting, Expense Information Used by CODM, Description					Net income attributable to Millrose, as presented on the Company’s unaudited condensed consolidated statements of operations, is a metric utilized by the CODM to assess the Reporting Segment’s performance and allocate resources. Total assets, as presented on the Company’s unaudited condensed consolidated balance sheets, is used to measure the Reporting Segment’s assets.
Cash		$ 66,600,000		$ 66,600,000	$ 66,600,000
Cash equivalents		0		0	0
Cash and cash equivalents		66,575,000		66,575,000	66,575,000		$ 0
Option fee and other related receivables		46.6		46.6	46.6		0
Option fee receivables		46,635,000		46,635,000	46,635,000
Total inventories		7,845,178,000		7,845,178,000	7,845,178,000		$ 5,465,290,000
Builder deposits prior to Spin-Off	$ 0
Development guarantee holdback liability		$ 100,000,000		$ 100,000,000	$ 100,000,000
Site improvement gurantee due period					10 days
Percentage of development guarantee		50.00%		50.00%	50.00%
Option fee revenues and other related income		$ 149,000,000	$ 0		$ 231,700,000	$ 0
Option fee revenues		141,100,000			221,200,000
Other related income for development loans		7,900,000			10,500,000
Management fee expense		21,960,000			34,064,000
Sales, general, and administrative expenses	$ 25,000,000		$ 59,800,000			$ 116,700,000
Other income (expense)		9,333,000			10,781,000
Interest expense		10,285,000			12,821,000
Interest income		1,818,000			$ 2,906,000
Kennedy Lewis Land and Residential Advisors LLC
Basis of presentation and significant accounting policies [Line Items]
Percentage of management fee paid					1.25%
Percentage of management fee quarterly payment					0.3125%
Management fee expense		22,000,000			$ 34,100,000
Post Spin-Off
Basis of presentation and significant accounting policies [Line Items]
Management fee expense		$ 22,000,000			$ 34,100,000
Master Option Agreement | Lennar
Basis of presentation and significant accounting policies [Line Items]
Percentage of total option fee revenue		95.00%			97.00%
Revolving Credit Facility
Basis of presentation and significant accounting policies [Line Items]
Deferred financing costs		$ 8,600,000		$ 8,600,000	$ 8,600,000
Amortization recorded to interest expense					1,300,000
Interest expense		10,300,000			12,800,000
Other expenses		800,000			800,000
DDTL Credit Facility
Basis of presentation and significant accounting policies [Line Items]
Deferred financing costs		13,800,000		13,800,000	13,800,000
Amortization recorded to interest expense					$ 200,000
Real Estate Investment Trust (REIT)
Basis of presentation and significant accounting policies [Line Items]
Percentage of taxable income					90.00%
Class A Common Stock
Basis of presentation and significant accounting policies [Line Items]
Dividends declared | $ / shares					$ 0.69
Class B Common Stock
Basis of presentation and significant accounting policies [Line Items]
Dividends declared | $ / shares					$ 0.69
Option Fee Receivables
Basis of presentation and significant accounting policies [Line Items]
Credit allowances		$ 0		$ 0	$ 0