Notes Payable - Components of Notes Payable (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Total	$ 24,563	$ 26,417
Unamortized discount	760	872
Notes payable to KMS' former shareholders
Debt Instrument [Line Items]
Unamortized discount	189	221
Notes payable to SSN's former shareholders
Debt Instrument [Line Items]
Unamortized discount	570	651
Notes Payable \| Notes payable to clearing firm under forgivable loans
Debt Instrument [Line Items]
Long-term debt	4,285	4,285
Notes Payable \| Note payable under subsidiary's term loan with bank
Debt Instrument [Line Items]
Long-term debt	47	153
Notes Payable \| Note payable under subsidiary's revolver with bank
Debt Instrument [Line Items]
Long-term debt	506	620
Notes Payable \| Notes payable by subsidiary to certain former shareholders of Highland
Debt Instrument [Line Items]
Long-term debt	6,738	6,738
Notes Payable \| Notes payable to KMS' former shareholders
Debt Instrument [Line Items]
Long-term debt	3,383	3,852
Notes Payable \| Notes payable to SSN's former shareholders
Debt Instrument [Line Items]
Long-term debt	$ 9,604	$ 10,769