Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies - Narrative (Details)

v3.20.1
Summary of Significant Accounting Policies - Narrative (Details) - USD ($)
Dec. 31, 2019
Jan. 01, 2019
Dec. 31, 2018
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]      
Investments with fair value below carrying value or in an unrealized loss position $ 0    
Allowance for doubtful accounts 0   $ 0
Operating lease right-of-use assets 3,436,000 $ 868,000 $ 0
Operating lease liability $ 16,217,000    
Accounting Standards Update 2016-02 [Member]      
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]      
Operating lease right-of-use assets   868,000  
Operating lease liability   $ 900,000