Debt - Summary of Outstanding Debt (Parenthetical) (Details)	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
One Market Plaza [Member]
Debt Instrument [Line Items]
Ownership interest rate of property	49.00%	49.00%
300 Mission Street [Member]
Debt Instrument [Line Items]
Ownership interest rate of property	31.10%	31.10%

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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