Fair Value Measurements - Schedule of Information About Fair Value Inputs Used to Calculate Fair Value (Details)
12 Months Ended
Dec. 31, 2018
ft²
Property
$ / ft²
Dec. 31, 2017
ft²
Property
$ / ft²
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)    
Impairment of lease, expiration period (or less) 60 days  
Number of impaired properties, long-lived assets held and used | Property 8 18
Number of impaired properties and buildings, long-lived assets held and used | Property 3  
Number of impaired properties, long-lived assets held for sale | Property 1 8
Fair Value Estimated Using Comparable Properties    
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)    
Number of impaired properties, long-lived assets held and used | Property   17
Fair Value Estimated Using Listing Price Or Broker Opinion Of Value    
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)    
Number of impaired properties, long-lived assets held and used | Property 5 1
Retail | Fair Value Estimated Using Comparable Properties    
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)    
Square Footage (in sq ft) | ft² 0 364,940
Retail | Fair Value Estimated Using Comparable Properties | Weighted Average    
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)    
Weighted Average Price (in dollars per sq ft) 0.00 55.68
Retail | Fair Value Estimated Using Comparable Properties | Minimum    
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)    
Weighted Average Price (in dollars per sq ft)   13.66
Retail | Fair Value Estimated Using Comparable Properties | Maximum    
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)    
Weighted Average Price (in dollars per sq ft)   305.05
Retail | Fair Value Estimated Using Listing Price Or Broker Opinion Of Value    
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)    
Square Footage (in sq ft) | ft² 27,302 22,500
Retail | Fair Value Estimated Using Listing Price Or Broker Opinion Of Value | Weighted Average    
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)    
Weighted Average Price (in dollars per sq ft) 507.11 88.89
Retail | Fair Value Estimated Using Listing Price Or Broker Opinion Of Value | Minimum    
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)    
Weighted Average Price (in dollars per sq ft) 185.42 88.89
Retail | Fair Value Estimated Using Listing Price Or Broker Opinion Of Value | Maximum    
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)    
Weighted Average Price (in dollars per sq ft) 638.72 88.89
Retail | Fair Value Estimated Using Signed Purchase And Sale Agreements    
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)    
Square Footage (in sq ft) | ft² 63,128 150,376
Retail | Fair Value Estimated Using Signed Purchase And Sale Agreements | Weighted Average    
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)    
Weighted Average Price (in dollars per sq ft) 126.73 230.52
Retail | Fair Value Estimated Using Signed Purchase And Sale Agreements | Minimum    
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)    
Weighted Average Price (in dollars per sq ft)   55.30
Retail | Fair Value Estimated Using Signed Purchase And Sale Agreements | Maximum    
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)    
Weighted Average Price (in dollars per sq ft)   346.23
Industrial | Fair Value Estimated Using Comparable Properties    
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)    
Square Footage (in sq ft) | ft² 0 370,824
Industrial | Fair Value Estimated Using Comparable Properties | Weighted Average    
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)    
Weighted Average Price (in dollars per sq ft) 0.00 5.35
Industrial | Fair Value Estimated Using Comparable Properties | Minimum    
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)    
Weighted Average Price (in dollars per sq ft)   3.30
Industrial | Fair Value Estimated Using Comparable Properties | Maximum    
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)    
Weighted Average Price (in dollars per sq ft)   8.56
Industrial | Fair Value Estimated Using Signed Purchase And Sale Agreements    
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)    
Square Footage (in sq ft) | ft² 0 223,747
Industrial | Fair Value Estimated Using Signed Purchase And Sale Agreements | Weighted Average    
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)    
Weighted Average Price (in dollars per sq ft) 0.00 37.09
Industrial | Fair Value Estimated Using Signed Purchase And Sale Agreements | Minimum    
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)    
Weighted Average Price (in dollars per sq ft)   24.02
Industrial | Fair Value Estimated Using Signed Purchase And Sale Agreements | Maximum    
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)    
Weighted Average Price (in dollars per sq ft)   54.21
Office | Fair Value Estimated Using Comparable Properties    
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)    
Square Footage (in sq ft) | ft² 0 161,346
Office | Fair Value Estimated Using Comparable Properties | Weighted Average    
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)    
Weighted Average Price (in dollars per sq ft) 0.00 40.14
Office | Fair Value Estimated Using Comparable Properties | Minimum    
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)    
Weighted Average Price (in dollars per sq ft)   24.82
Office | Fair Value Estimated Using Comparable Properties | Maximum    
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)    
Weighted Average Price (in dollars per sq ft)   244.86
Office | Fair Value Estimated Using Listing Price Or Broker Opinion Of Value    
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)    
Square Footage (in sq ft) | ft² 5,999 0
Office | Fair Value Estimated Using Listing Price Or Broker Opinion Of Value | Weighted Average    
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)    
Weighted Average Price (in dollars per sq ft) 225.04 0.00