Subsequent Events - Additional Information (Details)	Jul. 01, 2018 USD ($) ft²	Jun. 30, 2018 ft²
Subsequent Event [Line Items]
Area of office and retail properties		12,500,000
2099 Pennsylvania Avenue [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Area of office and retail properties	208,776
Sale agreement amount | $	$ 220,000,000