Dispositions (Narrative) (Details) ft² in Thousands, $ in Thousands			6 Months Ended
	Jun. 17, 2022 USD ($) ft²	Jan. 13, 2022 USD ($) property	Jun. 30, 2022 USD ($)	Jun. 30, 2021 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net proceeds from sale of real estate			$ 16,124	$ 72,216
Repayments of long-term debt			$ 1,240,573	$ 1,573,443
SoHo Properties
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of properties sold | property		2
Proceeds from sale of real estate held-for-investment		$ 84,500
Net proceeds from sale of real estate		81,399
Net gain on sale of real estate		$ 551
Center Building
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of real estate held-for-investment	$ 172,750
Net proceeds from sale of real estate	58,946
Net gain on sale of real estate	$ 15,213
Square footage of real estate property (in sqft) | ft²	498
Center Building | 33-00 Northern Boulevard mortgage loan interest rate swap
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Repayments of long-term debt	$ 100,000