Basis of Presentation and Significant Accounting Policies - Additional Information (Details)	1 Months Ended	2 Months Ended	3 Months Ended
	Feb. 07, 2025 USD ($) Segment	Mar. 31, 2025 USD ($) Segment	Mar. 31, 2025 USD ($) $ / shares	Mar. 31, 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		$ 89,500,000	$ 89,500,000
Cash equivalents		0	0
Cash and cash equivalents		89,523,000	89,523,000		$ 0
Option fee and other related receivables		47,200,000	47,200,000		0
Option fee receivables		47,206,000	47,206,000
Other related receivables		425,000	425,000
Total inventories		6,998,924,000	6,998,924,000		$ 5,465,290,000
Deferred financing costs		9,400,000	9,400,000
Amortization recorded to interest expense			200,000
Builder deposits prior to Spin-Off	$ 0
Development guarantee holdback liability		$ 100,000,000	$ 100,000,000
Site improvement gurantee due period			10 days
Percentage of development guarantee		50.00%	50.00%
Option fee revenues and other related income			$ 82,700,000	$ 0
Option fee revenues			80,100,000
Other related income for development loans			2,600,000
Management fee expense			12,104,000
Sales, general, and administrative expenses	$ 25,000,000			$ 56,900,000
Other income (expense)			1,448,000
Interest expense			2,536,000
Interest income			$ 1,088,000
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			$ 12,100,000
Post Spin-Off
Basis of presentation and significant accounting policies [Line Items]
Management fee expense			$ 12,100,000
Master Option Agreement | Lennar
Basis of presentation and significant accounting policies [Line Items]
Percentage of total option fee revenue			99.00%
Revolving Credit Facility
Basis of presentation and significant accounting policies [Line Items]
Other income (expense)			$ (2,500,000)
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			$ 0.38
Class B Common Stock
Basis of presentation and significant accounting policies [Line Items]
Dividends declared | $ / shares			$ 0.38
Option Fee Receivables
Basis of presentation and significant accounting policies [Line Items]
Credit allowances		$ 0	$ 0