Real Estate - Assets and Liabilities Held-for-sale (Details) - Held-for-sale - Woodcrest and Hearst Tower $ in Thousands	Dec. 31, 2020 USD ($)
Real estate asset and other assets held for sale
Operating properties, accumulated depreciation	$ 8,123
Operating property, net of accumulated depreciation of $8,123	106,864
Notes and accounts receivable	439
Deferred rents receivable	2,480
Intangible assets, accumulated amortization	6,065
Intangible assets, net of accumulated amortization of $6,065	15,830
Other assets	133
Total real estate asset and other assets held for sale	125,746
Liabilities of real estate asset held for sale
Accounts payable and accrued expenses	7,399
Deferred income	44
Intangible liabilities, accumulated amortization	1,205
Intangible liabilities, net of accumulated amortization of $1,205	3,014
Other liabilities	2,149
Total liabilities of real estate asset held for sale	$ 12,606