Commitments and contingencies (Details) - USD ($)	Jun. 30, 2025	Dec. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Performance and surety bonds	$ 42,800,000	$ 32,100,000
Letters of credit	$ 0	$ 0

Amount of performance and surety bonds that are available for the future payment of malpractice claims.

No definition available.

Name:	sdhc_MalpracticeLossContingencyPerformanceAndSuretyBonds
Namespace Prefix:	sdhc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant