Subsequent Events (Details) $ / shares in Units, ft² in Thousands, $ in Millions		1 Months Ended
	Oct. 28, 2020 $ / shares	Oct. 29, 2020 USD ($) ft² property $ / ft²	Sep. 30, 2020 ft²
Subsequent Event [Line Items]
Area of real estate property (in sq ft) | ft²			17,200
Subsequent Event
Subsequent Event [Line Items]
Common stock dividends (in dollars per share) | $ / shares	$ 0.21
Subsequent Event | 222 South Orange Avenue Building
Subsequent Event [Line Items]
Area of real estate property (in sq ft) | ft²		127
Payments to acquire real estate property | $		$ 20
Payments to acquire real estate property (in dollars per sq ft) | $ / ft²		157
Subsequent Event | New Jersey Assets
Subsequent Event [Line Items]
Number of assets disposed of | property		3
Proceeds from sale of property | $		$ 130
Proceeds from sale of real estate, proceeds (in dollars per sq ft) | $ / ft²		176