Noncontrolling Interests - Holders of Convertible Limited Partnership Units in the Operating Partnership (Details) - Noncontrolling Interests shares in Thousands	3 Months Ended
	Mar. 31, 2020 shares	Mar. 31, 2019 shares
Noncontrolling Interest [Line Items]
Limited partnership units (in shares)	7,900
Limited partnership units, conversion ratio	1
Outstanding stock percent that should be acquired for rights to be exercised	39.90%
Limited partnership units convertible into shares of common stock, eligible for conversion (in shares)	700
Fully converted partnership units and diluted weighted average shares outstanding (in shares)	31,200	30,700
Saul Holdings Limited Partnership
Noncontrolling Interest [Line Items]
Percentage of ownership interest of noncontrolling interest	25.40%