Annual report pursuant to Section 13 and 15(d)

Segment Information (Segment Information 1) (Details)

v2.4.1.9
Segment Information (Segment Information 1) (Details) (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Segment Reporting Information [Line Items]      
Commissions $ 445,734us-gaap_BrokerageCommissionsRevenue $ 394,414us-gaap_BrokerageCommissionsRevenue $ 326,132us-gaap_BrokerageCommissionsRevenue
Series A Preferred Stock      
Segment Reporting Information [Line Items]      
Commissions 5,148us-gaap_BrokerageCommissionsRevenue
/ us-gaap_StatementClassOfStockAxis
= us-gaap_SeriesAPreferredStockMember
   
Series A Preferred Stock | Ladenburg      
Segment Reporting Information [Line Items]      
Commissions 4,240us-gaap_BrokerageCommissionsRevenue
/ us-gaap_StatementBusinessSegmentsAxis
= lts_LadenburgThalmannAndCoIncMember
/ us-gaap_StatementClassOfStockAxis
= us-gaap_SeriesAPreferredStockMember
   
Series A Preferred Stock | Independent brokerage and advisory services      
Segment Reporting Information [Line Items]      
Commissions 908us-gaap_BrokerageCommissionsRevenue
/ us-gaap_StatementBusinessSegmentsAxis
= lts_IndependentBrokerageAndAdvisoryServicesMember
/ us-gaap_StatementClassOfStockAxis
= us-gaap_SeriesAPreferredStockMember
   
Employee brokerage commission expenses | Series A Preferred Stock      
Segment Reporting Information [Line Items]      
Commissions 2,603us-gaap_BrokerageCommissionsRevenue
/ us-gaap_IncomeStatementLocationAxis
= lts_EmployeebrokeragecommissionexpensesMember
/ us-gaap_StatementClassOfStockAxis
= us-gaap_SeriesAPreferredStockMember
   
Employee brokerage commission expenses | Series A Preferred Stock | Ladenburg      
Segment Reporting Information [Line Items]      
Commissions $ 2,545us-gaap_BrokerageCommissionsRevenue
/ us-gaap_IncomeStatementLocationAxis
= lts_EmployeebrokeragecommissionexpensesMember
/ us-gaap_StatementBusinessSegmentsAxis
= lts_LadenburgThalmannAndCoIncMember
/ us-gaap_StatementClassOfStockAxis
= us-gaap_SeriesAPreferredStockMember