Acquisitions, Dispositions and Assets Held for Sale (Details) ft² in Thousands, $ in Thousands	1 Months Ended
	Dec. 31, 2021 USD ($) ft²	Dec. 31, 2020 USD ($) ft²
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets held for sale	$ 73,876	$ 73,876
Disposal Group, Held-for-sale | Pen Place - Land Parcel | Arlington, Virginia
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Area of Real Estate Property | ft²	2,082	2,082
Assets held for sale	$ 73,876	$ 73,876
Disposal Group, Disposed of by Sale | Pen Place - Land Parcel | Arlington, Virginia
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gross Sales Price	198,000
Increase over previously disclosed contract price	$ 48,100