Annual report pursuant to Section 13 and 15(d)

Notes Payable (Notes Payable) (Details)

v3.8.0.1
Notes Payable (Notes Payable) (Details) - USD ($)
1 Months Ended 12 Months Ended
Dec. 12, 2017
Nov. 21, 2017
Jan. 02, 2015
Oct. 15, 2014
Feb. 28, 2018
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Jul. 31, 2014
Debt Instrument [Line Items]                  
Unamortized discount           $ 424,000 $ 872,000    
Note payable           96,849,000 26,417,000    
Interest paid           1,974,000 3,523,000 $ 3,807,000  
Brokerage commissions           535,979,000 510,023,000 558,683,000  
Notes payable to KMS                  
Debt Instrument [Line Items]                  
Unamortized discount           98,000 221,000    
Note payable           1,958,000 3,852,000    
Notes payable to SSN                  
Debt Instrument [Line Items]                  
Unamortized discount           326,000 651,000    
Note payable           6,074,000 10,769,000    
Senior Notes | 6.5% Senior Notes                  
Debt Instrument [Line Items]                  
Interest rate, stated percentage   6.50%              
Debt instrument, face amount $ 76,569,000 $ 72,500,000              
Redemption price percentage   100.00%              
Option for debt exercises 4,069,000                
Debt issuance costs 3,313,000                
Brokerage commissions $ 1,187,000                
Senior Notes | 6.5% Senior Notes | Subsequent event                  
Debt Instrument [Line Items]                  
Increase in debt instrument         $ 25,000,000        
Commissions receivable of gross sales (up to)         2.00%        
Highland | Promissory Notes | 10% Promissory Notes due February 26, 2019                  
Debt Instrument [Line Items]                  
Amount outstanding           6,738,000 6,738,000    
Interest rate, stated percentage                 10.00%
KMS | Promissory Notes                  
Debt Instrument [Line Items]                  
Periodic payment, principal and interest       $ 7,508,000          
Imputed interest rate       5.50%          
KMS | Promissory Notes | 1.84% Promissory Notes                  
Debt Instrument [Line Items]                  
Interest rate, stated percentage       1.84%          
Term       4 years          
Debt instrument, face amount       $ 8,000,000          
Unamortized discount           98,000 221,000    
KMS | Promissory Notes | 1.84% Promissory Notes | Board of Directors Chairman                  
Debt Instrument [Line Items]                  
Long-term debt           612,000      
KMS | Promissory Notes | 1.84% Promissory Notes | President                  
Debt Instrument [Line Items]                  
Long-term debt           225,000      
KMS | Promissory Notes | 1.84% Promissory Notes | Officer                  
Debt Instrument [Line Items]                  
Interest expense           22,000 37,000 $ 51,000  
KMS | Subordinated Notes | Prime Rate                  
Debt Instrument [Line Items]                  
Interest rate at period end               3.50%  
SSN | Promissory Notes                  
Debt Instrument [Line Items]                  
Periodic payment, principal and interest     $ 18,697,000            
Imputed interest rate     5.10%            
SSN | Promissory Notes | 1.84% Promissory Notes                  
Debt Instrument [Line Items]                  
Debt instrument, face amount     $ 20,000,000            
SSN | Promissory Notes | 1.84% Promissory Notes | President                  
Debt Instrument [Line Items]                  
Debt instrument, face amount           128,000      
SSN | Promissory Notes | 1.84% Promissory Notes | Officer                  
Debt Instrument [Line Items]                  
Interest expense           3,000 5,000    
SSN | Promissory Notes | 1.74% Promissory Notes                  
Debt Instrument [Line Items]                  
Interest rate, stated percentage     1.74%            
Term     4 years            
Imputed interest rate     5.10%            
Unamortized discount           $ 326,000 $ 651,000    
Management | Senior Notes | 6.5% Senior Notes                  
Debt Instrument [Line Items]                  
Senior notes purchased by management and Board of Directors   $ 10,400,000