Variable interest entities (Details) - Option Contracts [Member] - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Summary of Interests in Land Option Agreements [Abstract]
Deposits	$ 66.3	$ 57.1
Remaining purchase price	$ 834.4	$ 652.1

Amount of remaining purchase price in land option contracts.

No definition available.

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