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Commitments and Contingencies - Narrative (Details) - USD ($)
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 21, 2001
Commitments and Contingencies [Line Items]      
Accrued liabilities related to retained risks $ 93,500,000 $ 142,000,000.0  
Minimum      
Commitments and Contingencies [Line Items]      
Lease term 1 year    
Maximum      
Commitments and Contingencies [Line Items]      
Lease term 20 years    
Contingent Promissory Note      
Commitments and Contingencies [Line Items]      
Principal amount of contingent promissory note $ 40,000,000    
Promissory note term 20 years    
Contingent promissory note, maximum amount including interest $ 96,000,000    
DFA      
Commitments and Contingencies [Line Items]      
Acquired interest (as a percent)     33.80%