Loan Securitization/Sale Activities - Narrative (Details) - USD ($)	3 Months Ended
Mar. 31, 2023	Mar. 31, 2022
Commercial and Residential Lending Segment
Loan Transfer Activities
Loans held-for-sale face amount	$ 0	$ 0
Infrastructure Lending Segment
Loan Transfer Activities
Loans held-for-sale face amount	$ 0	$ 0

Represents the par value of loans held-for-sale, sold during the period.

No definition available.

Name:	stwd_LoansHeldForSaleSoldParValue
Namespace Prefix:	stwd_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration