Shareholder Report, Average Annual Return (Details)	12 Months Ended	60 Months Ended	111 Months Ended	120 Months Ended
Shareholder Report, Average Annual Return (Details)	May 31, 2025	May 31, 2025	May 31, 2025	May 31, 2025
Without Sales Load [Member] \| C000129667
Average Annual Return [Line Items]
Average Annual Return, Percent	7.62%	7.00%		5.94%
Without Sales Load [Member] \| C000129666
Average Annual Return [Line Items]
Average Annual Return, Percent	7.34%	6.71%		5.67%
Without Sales Load [Member] \| C000169044
Average Annual Return [Line Items]
Average Annual Return, Percent	7.78%	7.16%	7.43%
Russell 3000 Index
Average Annual Return [Line Items]
Average Annual Return, Percent	13.12%	15.34%		12.21%
Russell 3000 Index
Average Annual Return [Line Items]
Average Annual Return, Percent	13.12%	15.34%		12.21%
Russell 3000 Index
Average Annual Return [Line Items]
Average Annual Return, Percent	13.12%	15.34%	14.27%
S&P Target Date 2025 Index
Average Annual Return [Line Items]
Average Annual Return, Percent	8.82%	7.23%		6.16%
S&P Target Date 2025 Index
Average Annual Return [Line Items]
Average Annual Return, Percent	8.82%	7.23%		6.16%
S&P Target Date 2025 Index
Average Annual Return [Line Items]
Average Annual Return, Percent	8.82%	7.23%	7.47%