v3.26.1
Shareholder Report, Average Annual Return (Details) 193137_Themes Transatlantic Defense ETF_TF_TSR Annual {TF}
12 Months Ended
Sep. 30, 2025
Sep. 30, 2025
Themes Transatlantic Defense ETF    
Average Annual Return [Line Items]    
Line Graph and Table Measure Name   Themes Transatlantic Defense ETF NAV
Average Annual Return, Percent   55.70%
MSCI ACWI Net Total Return Index (USD)    
Average Annual Return [Line Items]    
Line Graph and Table Measure Name MSCI ACWI Net Total Return Index (USD)  
Average Annual Return, Percent 17.73%  
Solactive Transatlantic Aerospace and Defense Index NTR    
Average Annual Return [Line Items]    
Line Graph and Table Measure Name Solactive Transatlantic Aerospace and Defense Index NTR  
Average Annual Return, Percent 56.19%