Shareholder Report, Average Annual Return (Details)	12 Months Ended	60 Months Ended	120 Months Ended
Shareholder Report, Average Annual Return (Details)	May 31, 2026	May 31, 2026	May 31, 2026
Without Sales Load [Member] \| C000129667
Average Annual Return [Line Items]
Average Annual Return, Percent	13.58%	4.94%	7.45%
Without Sales Load [Member] \| C000129666
Average Annual Return [Line Items]
Average Annual Return, Percent	13.32%	4.68%	7.18%
Without Sales Load [Member] \| C000169044
Average Annual Return [Line Items]
Average Annual Return, Percent	13.84%	5.12%	7.62%
Russell 3000 Index
Average Annual Return [Line Items]
Average Annual Return, Percent	29.45%	12.92%	15.12%
Russell 3000 Index
Average Annual Return [Line Items]
Average Annual Return, Percent	29.45%	12.92%	15.12%
Russell 3000 Index
Average Annual Return [Line Items]
Average Annual Return, Percent	29.45%	12.92%	15.12%
S&P Target Date 2025 Index
Average Annual Return [Line Items]
Average Annual Return, Percent	16.73%	6.14%	7.91%
S&P Target Date 2025 Index
Average Annual Return [Line Items]
Average Annual Return, Percent	16.73%	6.14%	7.91%
S&P Target Date 2025 Index
Average Annual Return [Line Items]
Average Annual Return, Percent	16.73%	6.14%	7.91%