Quarterly report pursuant to Section 13 or 15(d)

Net Capital Requirements (Details)

v3.10.0.1
Net Capital Requirements (Details) - USD ($)
Jun. 30, 2018
Dec. 31, 2017
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]    
Stockholder's equity $ 390,466,000 $ 370,379,000
Securities America    
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]    
Regulatory net capital 10,599,000  
Securities America | Minimum    
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]    
Alternative minimum net capital requirement 250,000  
Triad    
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]    
Regulatory net capital 7,735,000  
Triad | Minimum    
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]    
Alternative minimum net capital requirement 250,000  
Investacorp Inc.    
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]    
Regulatory net capital 8,577,000  
Investacorp Inc. | Minimum    
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]    
Alternative minimum net capital requirement 250,000  
KMS Financial Services, Inc. (KMS)    
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]    
Regulatory net capital 7,654,000  
KMS Financial Services, Inc. (KMS) | Minimum    
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]    
Alternative minimum net capital requirement 250,000  
Securities Service Network, Inc. (SSN)    
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]    
Regulatory net capital 7,219,000  
Ladenburg    
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]    
Regulatory net capital 26,636,000  
Ladenburg | Minimum    
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]    
Alternative minimum net capital requirement 250,000  
Premier    
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]    
Stockholder's equity 2,272,000  
Premier | Minimum    
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]    
Stockholder's equity 1,000,000  
Premier | Minimum | Cash    
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]    
Stockholder's equity $ 250,000