Organization, Basis of Presentation - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2020 property store tenant partnership
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Distribution of REIT taxable income (excluding net capital gains) to its stockholders	90.00%
Number of partnerships | partnership	2
Number of stores | store	33
Saul Holdings Limited Partnership
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Percentage of ownership in operating partnership	74.60%
Shopping Centers
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Number of real estate properties	50
Mixed-Use Properties
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Number of real estate properties	7
Non-operating Development Properties
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Number of real estate properties	3
Revenue Benchmark
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Number of tenants | tenant	1
Percentage of total revenue	2.50%
Revenue Benchmark | Giant Food
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Number of stores | store	11
Percentage of total revenue	5.40%