Loans Payable - Schedule of outstanding loans payable (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2022	Dec. 31, 2021
Loans Payable - Schedule of outstanding mortgage loans payable secured by properties [Line Items]
Total Principal Outstanding	$ 2,169.0	$ 2,362.6
Fair Value Adjustment	(44.0)	17.9
Total Loans Payable	$ 2,125.0	2,380.5
Fusion 1560
Loans Payable - Schedule of outstanding mortgage loans payable secured by properties [Line Items]
Interest Rate	3.42%
Annual Interest Rate and Payment Frequency	3.42% paid monthly
Principal Amounts Outstanding	$ 0.0	37.4
Maturity	Jun. 10, 2022
The Colorado
Loans Payable - Schedule of outstanding mortgage loans payable secured by properties [Line Items]
Interest Rate	3.69%
Annual Interest Rate and Payment Frequency	3.69% paid monthly
Principal Amounts Outstanding	$ 0.0	84.7
Maturity	Nov. 01, 2022
The Legacy at Westwood
Loans Payable - Schedule of outstanding mortgage loans payable secured by properties [Line Items]
Interest Rate	3.69%
Annual Interest Rate and Payment Frequency	3.69% paid monthly
Principal Amounts Outstanding	$ 0.0	43.2
Maturity	Nov. 01, 2022
Regents Court
Loans Payable - Schedule of outstanding mortgage loans payable secured by properties [Line Items]
Interest Rate	3.69%
Annual Interest Rate and Payment Frequency	3.69% paid monthly
Principal Amounts Outstanding	$ 0.0	36.6
Maturity	Nov. 01, 2022
1001 Pennsylvania Avenue
Loans Payable - Schedule of outstanding mortgage loans payable secured by properties [Line Items]
Interest Rate	3.70%
Annual Interest Rate and Payment Frequency	3.70% paid monthly
Principal Amounts Outstanding	$ 302.9	308.1
Maturity	Jun. 01, 2023
Biltmore at Midtown
Loans Payable - Schedule of outstanding mortgage loans payable secured by properties [Line Items]
Interest Rate	3.94%
Annual Interest Rate and Payment Frequency	3.94% paid monthly
Principal Amounts Outstanding	$ 36.4	36.4
Maturity	Jul. 05, 2023
Cherry Knoll
Loans Payable - Schedule of outstanding mortgage loans payable secured by properties [Line Items]
Interest Rate	3.78%
Annual Interest Rate and Payment Frequency	3.78% paid monthly
Principal Amounts Outstanding	$ 35.3	35.3
Maturity	Jul. 05, 2023
Lofts at SoDo
Loans Payable - Schedule of outstanding mortgage loans payable secured by properties [Line Items]
Interest Rate	3.94%
Annual Interest Rate and Payment Frequency	3.94% paid monthly
Principal Amounts Outstanding	$ 35.1	35.1
Maturity	Jul. 05, 2023
San Diego Office Portfolio
Loans Payable - Schedule of outstanding mortgage loans payable secured by properties [Line Items]
Interest Rate	4.73%
Annual Interest Rate and Payment Frequency	4.73% paid monthly
Principal Amounts Outstanding, loans payable	$ 58.2	51.4
Maturity, loans payable	Aug. 09, 2023
Pacific City
Loans Payable - Schedule of outstanding mortgage loans payable secured by properties [Line Items]
Annual Interest Rate and Payment Frequency	2.00% + LIBOR paid monthly
Principal Amounts Outstanding	$ 105.0	105.0
Maturity	Oct. 01, 2023
The Stratum
Loans Payable - Schedule of outstanding mortgage loans payable secured by properties [Line Items]
Interest Rate	2.45%
Annual Interest Rate and Payment Frequency	2.45% paid monthly
Principal Amounts Outstanding	$ 40.0	39.8
Maturity	May 09, 2024
Spring House Innovation Park
Loans Payable - Schedule of outstanding mortgage loans payable secured by properties [Line Items]
Annual Interest Rate and Payment Frequency	1.25% + LIBOR paid monthly
Principal Amounts Outstanding	$ 48.7	40.5
Maturity	Jul. 09, 2024
1401 H Street NW
Loans Payable - Schedule of outstanding mortgage loans payable secured by properties [Line Items]
Interest Rate	3.65%
Annual Interest Rate and Payment Frequency	3.65% paid monthly
Principal Amounts Outstanding	$ 115.0	115.0
Maturity	Nov. 05, 2024
The District on La Frontera | Loan A
Loans Payable - Schedule of outstanding mortgage loans payable secured by properties [Line Items]
Interest Rate	3.84%
Annual Interest Rate and Payment Frequency	3.84% paid monthly
Principal Amounts Outstanding	$ 37.2	37.8
Maturity	Dec. 01, 2024
The District on La Frontera | Loan B
Loans Payable - Schedule of outstanding mortgage loans payable secured by properties [Line Items]
Interest Rate	4.96%
Annual Interest Rate and Payment Frequency	4.96% paid monthly
Principal Amounts Outstanding	$ 4.2	4.2
Maturity	Dec. 01, 2024
Circa Green Lake
Loans Payable - Schedule of outstanding mortgage loans payable secured by properties [Line Items]
Interest Rate	3.71%
Annual Interest Rate and Payment Frequency	3.71% paid monthly
Principal Amounts Outstanding	$ 52.0	52.0
Maturity	Mar. 05, 2025
Union - South Lake Union
Loans Payable - Schedule of outstanding mortgage loans payable secured by properties [Line Items]
Interest Rate	3.66%
Annual Interest Rate and Payment Frequency	3.66% paid monthly
Principal Amounts Outstanding	$ 57.0	57.0
Maturity	Mar. 05, 2025
Holly Street Village
Loans Payable - Schedule of outstanding mortgage loans payable secured by properties [Line Items]
Interest Rate	3.65%
Annual Interest Rate and Payment Frequency	3.65% paid monthly
Principal Amounts Outstanding	$ 81.0	81.0
Maturity	May 01, 2025
Henley at Kingstowne
Loans Payable - Schedule of outstanding mortgage loans payable secured by properties [Line Items]
Interest Rate	3.60%
Annual Interest Rate and Payment Frequency	3.60% paid monthly
Principal Amounts Outstanding	$ 68.0	69.1
Maturity	May 01, 2025
32 South State Street
Loans Payable - Schedule of outstanding mortgage loans payable secured by properties [Line Items]
Interest Rate	4.48%
Annual Interest Rate and Payment Frequency	4.48% paid monthly
Principal Amounts Outstanding	$ 24.0	24.0
Maturity	Jun. 06, 2025
Vista Station Office Portfolio | Loan A
Loans Payable - Schedule of outstanding mortgage loans payable secured by properties [Line Items]
Interest Rate	4.00%
Annual Interest Rate and Payment Frequency	4.00% paid monthly
Principal Amounts Outstanding	$ 18.8	19.3
Maturity	Jul. 01, 2025
Vista Station Office Portfolio | Loan B
Loans Payable - Schedule of outstanding mortgage loans payable secured by properties [Line Items]
Interest Rate	4.20%
Annual Interest Rate and Payment Frequency	4.20% paid monthly
Principal Amounts Outstanding	$ 42.2	42.9
Maturity	Nov. 01, 2025
780 Third Avenue | Loan A
Loans Payable - Schedule of outstanding mortgage loans payable secured by properties [Line Items]
Interest Rate	3.55%
Annual Interest Rate and Payment Frequency	3.55% paid monthly
Principal Amounts Outstanding	$ 150.0	150.0
Maturity	Aug. 01, 2025
780 Third Avenue | Loan B
Loans Payable - Schedule of outstanding mortgage loans payable secured by properties [Line Items]
Interest Rate	3.55%
Annual Interest Rate and Payment Frequency	3.55% paid monthly
Principal Amounts Outstanding	$ 20.0	20.0
Maturity	Aug. 01, 2025
Reserve at Chino Hills
Loans Payable - Schedule of outstanding mortgage loans payable secured by properties [Line Items]
Annual Interest Rate and Payment Frequency	1.50% + LIBOR paid monthly
Principal Amounts Outstanding	$ 72.5	68.2
Maturity	Aug. 09, 2025
Sixth & Main
Loans Payable - Schedule of outstanding mortgage loans payable secured by properties [Line Items]
Annual Interest Rate and Payment Frequency	1.87% + LIBOR paid monthly
Principal Amounts Outstanding	$ 41.1	40.4
Maturity	Nov. 09, 2025
701 Brickell Avenue
Loans Payable - Schedule of outstanding mortgage loans payable secured by properties [Line Items]
Interest Rate	3.66%
Annual Interest Rate and Payment Frequency	3.66% paid monthly
Principal Amounts Outstanding	$ 179.4	182.0
Maturity	Apr. 01, 2026
Marketplace at Mill Creek
Loans Payable - Schedule of outstanding mortgage loans payable secured by properties [Line Items]
Interest Rate	3.82%
Annual Interest Rate and Payment Frequency	3.82% paid monthly
Principal Amounts Outstanding	$ 39.6	39.6
Maturity	Sep. 11, 2027
Overlook At King Of Prussia
Loans Payable - Schedule of outstanding mortgage loans payable secured by properties [Line Items]
Interest Rate	3.82%
Annual Interest Rate and Payment Frequency	3.82% paid monthly
Principal Amounts Outstanding	$ 40.8	40.8
Maturity	Sep. 11, 2027
Winslow Bay
Loans Payable - Schedule of outstanding mortgage loans payable secured by properties [Line Items]
Interest Rate	3.82%
Annual Interest Rate and Payment Frequency	3.82% paid monthly
Principal Amounts Outstanding	$ 25.8	25.8
Maturity	Sep. 11, 2027
1900 K Street, NW
Loans Payable - Schedule of outstanding mortgage loans payable secured by properties [Line Items]
Interest Rate	3.93%
Annual Interest Rate and Payment Frequency	3.93% paid monthly
Principal Amounts Outstanding	$ 161.8	163.0
Maturity	Apr. 01, 2028
99 High Street
Loans Payable - Schedule of outstanding mortgage loans payable secured by properties [Line Items]
Interest Rate	3.90%
Annual Interest Rate and Payment Frequency	3.90% paid monthly
Principal Amounts Outstanding	$ 277.0	$ 277.0
Maturity	Mar. 01, 2030
LIBOR | Pacific City
Loans Payable - Schedule of outstanding mortgage loans payable secured by properties [Line Items]
Annual Interest Rate, basis spread on variable rate	2.00%
LIBOR | Spring House Innovation Park
Loans Payable - Schedule of outstanding mortgage loans payable secured by properties [Line Items]
Annual Interest Rate, basis spread on variable rate	1.25%
LIBOR | Reserve at Chino Hills
Loans Payable - Schedule of outstanding mortgage loans payable secured by properties [Line Items]
Annual Interest Rate, basis spread on variable rate	1.50%
LIBOR | Sixth & Main
Loans Payable - Schedule of outstanding mortgage loans payable secured by properties [Line Items]
Annual Interest Rate, basis spread on variable rate	1.87%