• Filing Date: 2019-03-08
  • Form Type: 10-K
  • Description: Annual report
v3.10.0.1
Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Dec. 15, 2016
Summary Of Significant Accounting Policies [Line Items]        
Percentage of investment in unconsolidated entities 90.00%     90.00%
Period for establishing allowance on insurance premiums receivable 90 days      
Allowance on insurance premiums receivable $ 0 $ 0    
Operating expenses totaling reclassified to general and administrative personnel expenses     $ 7,163,000  
Net cash provided by operating activities $ 28,595,000 16,635,000 88,275,000  
Accounting Standards Update 2016-18 [Member]        
Summary Of Significant Accounting Policies [Line Items]        
Net cash provided by operating activities   16,635,000 88,275,000  
Accounting Standards Update 2016-18 [Member] | Previously Reported [Member]        
Summary Of Significant Accounting Policies [Line Items]        
Net cash provided by operating activities   16,426,000 $ 87,975,000  
Accounting Standards Update 2016-01 [Member]        
Summary Of Significant Accounting Policies [Line Items]        
Cumulative effect amount of the after-tax net unrealized holding gains   4,168,000    
Equity securities, available for sale, at fair value   58,911,000    
Equity securities, trading, at fair value   1,045,000    
Accounting Standards Update 2018-02 [Member]        
Summary Of Significant Accounting Policies [Line Items]        
Cumulative effect amount of stranded tax effects   $ 984,000    
Capitalized Software Cost [Member]        
Summary Of Significant Accounting Policies [Line Items]        
Estimated useful life 7 years      
Building [Member]        
Summary Of Significant Accounting Policies [Line Items]        
Useful lives of Property and Equipment 39 years      
Computer Hardware and Software [Member]        
Summary Of Significant Accounting Policies [Line Items]        
Useful lives of Property and Equipment 3 years      
Minimum [Member] | Office Furniture and Equipment [Member]        
Summary Of Significant Accounting Policies [Line Items]        
Useful lives of Property and Equipment 3 years      
Maximum [Member] | Office Furniture and Equipment [Member]        
Summary Of Significant Accounting Policies [Line Items]        
Useful lives of Property and Equipment 7 years      
Investment in Joint Venture [Member]        
Summary Of Significant Accounting Policies [Line Items]        
Percentage of investment in unconsolidated entities 90.00%