Annual report pursuant to Section 13 and 15(d)

Securities Owned and Securities Sold, But Not Yet Purchased (Narrative) (Details)

v2.4.1.9
Securities Owned and Securities Sold, But Not Yet Purchased (Narrative) (Details) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Securities owned deposited with the Company's subsidiaries clearing broker $ 5,429lts_SecuritiesOwnedAndHeldAtClearingBroker $ 4,014lts_SecuritiesOwnedAndHeldAtClearingBroker
Securities owned, at fair value 5,910us-gaap_SecurityOwnedAndSoldNotYetPurchasedFairValueSecurityOwned 4,789us-gaap_SecurityOwnedAndSoldNotYetPurchasedFairValueSecurityOwned
Level 2 [Member]    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Securities owned, at fair value 3,464us-gaap_SecurityOwnedAndSoldNotYetPurchasedFairValueSecurityOwned
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
4,076us-gaap_SecurityOwnedAndSoldNotYetPurchasedFairValueSecurityOwned
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
Common Stock and Warrants [Member]    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Securities owned, at fair value 1,981us-gaap_SecurityOwnedAndSoldNotYetPurchasedFairValueSecurityOwned
/ us-gaap_SecurityOwnedAndSoldNotYetPurchasedAtFairValueAxis
= lts_CommonStockAndWarrantsMember
689us-gaap_SecurityOwnedAndSoldNotYetPurchasedFairValueSecurityOwned
/ us-gaap_SecurityOwnedAndSoldNotYetPurchasedAtFairValueAxis
= lts_CommonStockAndWarrantsMember
Common Stock and Warrants [Member] | Warrants to purchase common stock | Level 2 [Member]    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Securities owned, at fair value $ 403us-gaap_SecurityOwnedAndSoldNotYetPurchasedFairValueSecurityOwned
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_InvestmentTypeAxis
= us-gaap_WarrantMember
/ us-gaap_SecurityOwnedAndSoldNotYetPurchasedAtFairValueAxis
= lts_CommonStockAndWarrantsMember
$ 534us-gaap_SecurityOwnedAndSoldNotYetPurchasedFairValueSecurityOwned
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel2Member
/ us-gaap_InvestmentTypeAxis
= us-gaap_WarrantMember
/ us-gaap_SecurityOwnedAndSoldNotYetPurchasedAtFairValueAxis
= lts_CommonStockAndWarrantsMember