Shareholder Report, Average Annual Return (Details)	12 Months Ended	17 Months Ended	21 Months Ended
Shareholder Report, Average Annual Return (Details)	Jul. 31, 2025	Jul. 31, 2025	Jul. 31, 2025
C000246109 [Member]
Average Annual Return [Line Items]
Line Graph and Table Measure Name	First Trust Core Investment Grade ETF
Average Annual Return, Percent	4.13%		7.46%
C000248162 [Member]
Average Annual Return [Line Items]
Line Graph and Table Measure Name	First Trust Commercial Mortgage Opportunities ETF
Average Annual Return, Percent	6.08%	6.71%
C000248350 [Member]
Average Annual Return [Line Items]
Line Graph and Table Measure Name	First Trust Structured Credit Income Opportunities ETF
Average Annual Return, Percent	8.85%	9.13%
Bloomberg US Aggregate Bond Index [Member]
Average Annual Return [Line Items]
Line Graph and Table Measure Name	Bloomberg US Aggregate Bond Index
Average Annual Return, Percent	3.38%	5.07%	6.44%
ICE BofA US Broad Market Index [Member]
Average Annual Return [Line Items]
Line Graph and Table Measure Name	ICE BofA US Broad Market Index
Average Annual Return, Percent	3.40%		6.49%
Bloomberg Non Agency Investment Grade CMBS US Aggregate Eligible Aaa Index [Member]
Average Annual Return [Line Items]
Line Graph and Table Measure Name	Bloomberg Non-Agency Investment Grade CMBS: US Aggregate Eligible Aaa Index
Average Annual Return, Percent	6.10%	6.86%
ICE BofA US ABS And CMBS Index [Member]
Average Annual Return [Line Items]
Line Graph and Table Measure Name	ICE BofA US ABS & CMBS Index
Average Annual Return, Percent	5.57%	6.40%