Investment in Real Estate - Acquisition Information (Details) $ in Millions					12 Months Ended
	Oct. 23, 2018 USD ($) ft²	Oct. 09, 2018 USD ($) ft²	Aug. 31, 2018 USD ($) ft²	Jun. 07, 2018 USD ($) ft²	Dec. 31, 2019	Dec. 31, 2018 USD ($) ft²
Real Estate Properties [Line Items]
Acquisitions, square feet \| ft²						916,701
Acquisitions, purchase price \| $						$ 521.0
6605 Eleanor Avenue \| Studio Segment
Real Estate Properties [Line Items]
Acquisitions, square feet \| ft²				22,823
Acquisitions, purchase price \| $				$ 18.0
1034 Seward Street \| Studio Segment
Real Estate Properties [Line Items]
Acquisitions, square feet \| ft²				18,673
Acquisitions, purchase price \| $				$ 12.0
One Westside and 10850 Pico \| VIE, primary beneficiary
Real Estate Properties [Line Items]
VIE, ownership percentage					75.00%
One Westside and 10850 Pico \| Office
Real Estate Properties [Line Items]
Acquisitions, square feet \| ft²			595,987
Acquisitions, purchase price \| $			$ 190.0
Ferry Building \| VIE, primary beneficiary
Real Estate Properties [Line Items]
VIE, ownership percentage					55.00%
Ferry Building \| Office
Real Estate Properties [Line Items]
Acquisitions, square feet \| ft²		268,018
Acquisitions, purchase price \| $		$ 291.0
6660 Santa Monica \| Studio Segment
Real Estate Properties [Line Items]
Acquisitions, square feet \| ft²	11,200
Acquisitions, purchase price \| $	$ 10.0