Noncontrolling Interests (Property Partnerships) (Narrative) (Details) - USD ($) $ in Thousands |
May 12, 2016 |
Jun. 30, 2018 |
Dec. 31, 2017 |
---|---|---|---|
Noncontrolling Interest [Line Items] | |||
Noncontrolling Interest in Limited Partnerships | $ 1,699,181 | $ 1,683,760 | |
Salesforce Tower[Member] | Consolidated Properties [Member] | |||
Noncontrolling Interest [Line Items] | |||
Portion of project costs covered by a construction loan | 50.00% | ||
Portion of costs funded (in percentage) | 50.00% | ||
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners | 5.00% | ||
Debt Instrument, Basis Spread on Variable Rate | 3.00% | ||
Salesforce Tower[Member] | Parent Company [Member] | Consolidated Properties [Member] | |||
Noncontrolling Interest [Line Items] | |||
Costs funded (in percentage) | 2.50% | ||
Preferred equity funded | $ 20,700 |