Consolidated Statement of Equity (Unaudited) - USD ($) $ in Thousands	Total	Dividend Distributions Payable	Series D Cumulative Redeemable Preferred Stock	Series D Cumulative Redeemable Preferred Stock Dividend Distributions Payable	Series C Cumulative Preferred Stock	Series C Cumulative Preferred Stock Dividend Paid	Series C Cumulative Preferred Stock Dividend Distributions Payable	Total Saul Centers, Inc.	Total Saul Centers, Inc. Dividend Distributions Payable	Total Saul Centers, Inc. Series D Cumulative Redeemable Preferred Stock	Total Saul Centers, Inc. Series D Cumulative Redeemable Preferred Stock Dividend Distributions Payable	Total Saul Centers, Inc. Series C Cumulative Preferred Stock	Total Saul Centers, Inc. Series C Cumulative Preferred Stock Dividend Paid	Total Saul Centers, Inc. Series C Cumulative Preferred Stock Dividend Distributions Payable	Preferred Stock	Preferred Stock Series D Cumulative Redeemable Preferred Stock	Preferred Stock Series C Cumulative Preferred Stock	Common Stock	Additional Paid-in Capital	Additional Paid-in Capital Series D Cumulative Redeemable Preferred Stock	Additional Paid-in Capital Series C Cumulative Preferred Stock	Distributions in Excess of Accumulated Earnings	Distributions in Excess of Accumulated Earnings Dividend Distributions Payable	Distributions in Excess of Accumulated Earnings Series D Cumulative Redeemable Preferred Stock Dividend Distributions Payable	Distributions in Excess of Accumulated Earnings Series C Cumulative Preferred Stock	Distributions in Excess of Accumulated Earnings Series C Cumulative Preferred Stock Dividend Paid	Distributions in Excess of Accumulated Earnings Series C Cumulative Preferred Stock Dividend Distributions Payable	Accumulated Other Comprehensive (Loss)	Noncontrolling Interest	Noncontrolling Interest Dividend Distributions Payable
Beginning Balance at Dec. 31, 2017	$ 393,103							$ 334,405							$ 180,000			$ 221	$ 352,590			$ (197,710)						$ (696)	$ 58,698
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of 30,000 shares of Series D Cumulative preferred stock			$ 72,369							$ 72,369						$ 75,000				$ (2,631)
Redemption of 30,000 shares of Series C Cumulative preferred stock					$ (75,017)							$ (75,017)					$ (75,000)				$ 2,311				$ (2,328)
Issuance of common stock:
Issuance of shares pursuant to dividend reinvestment plan	3,677							3,677										1	3,676
Issuance of shares due to exercise of employee stock options, director share grant and issuance of directors’ deferred shares	769							769											769
Issuance of 38,037 partnership units pursuant to dividend reinvestment plan	2,017																												2,017
Net income	14,947							12,588														12,588							2,359
Change in unrealized loss on cash flow hedge	389							289																				289	100
Preferred stock distributions:
Preferred stock distributions				$ (868)		$ (730)	$ (1,805)				$ (868)		$ (730)	$ (1,805)										$ (868)		$ (730)	$ (1,805)
Common stock distributions payable		$ (15,494)							$ (11,552)														$ (11,552)							$ (3,942)
Ending Balance at Mar. 31, 2018	393,357							334,125							180,000			222	356,715			(202,405)						(407)	59,232
Beginning Balance at Dec. 31, 2018	425,220							355,912							180,000			227	384,533			(208,593)						(255)	69,308
Issuance of common stock:
Issuance of shares pursuant to dividend reinvestment plan	6,171							6,171										1	6,170
Issuance of shares due to exercise of employee stock options, director share grant and issuance of directors’ deferred shares	420							420										1	419
Issuance of 13,742 partnership units pursuant to dividend reinvestment plan	705																												705
Net income	17,077							13,447														13,447							3,630
Change in unrealized loss on cash flow hedge	(46)							(34)																				(34)	(12)
Preferred stock distributions:
Preferred stock distributions				$ (1,148)			$ (1,805)				$ (1,148)			$ (1,805)										$ (1,148)			$ (1,805)
Common stock distributions payable		$ (16,263)							$ (12,108)														$ (12,108)							$ (4,155)
Ending Balance at Mar. 31, 2019	$ 430,331							$ 360,855							$ 180,000			$ 229	$ 391,122			$ (210,207)						$ (289)	$ 69,476