v3.26.1
Shareholder Report, Line Graph (Details) - USD ($)
 3 Months Ended 6 Months Ended 9 Months Ended 12 Months Ended 15 Months Ended 18 Months Ended 21 Months Ended 24 Months Ended 27 Months Ended 30 Months Ended 33 Months Ended 36 Months Ended 39 Months Ended 42 Months Ended 45 Months Ended 48 Months Ended 51 Months Ended 54 Months Ended 57 Months Ended 60 Months Ended 63 Months Ended 66 Months Ended 69 Months Ended 72 Months Ended 75 Months Ended 78 Months Ended 81 Months Ended 84 Months Ended 87 Months Ended 90 Months Ended 93 Months Ended 96 Months Ended 99 Months Ended 102 Months Ended 105 Months Ended 108 Months Ended 111 Months Ended 114 Months Ended 117 Months Ended 120 Months Ended
May 31, 2016
Aug. 31, 2016
Nov. 30, 2016
Feb. 28, 2017
May 31, 2017
Aug. 31, 2017
Nov. 30, 2017
Feb. 28, 2018
May 31, 2018
Aug. 31, 2018
Nov. 30, 2018
Feb. 28, 2019
May 31, 2019
Aug. 31, 2019
Nov. 30, 2019
Feb. 29, 2020
May 31, 2020
Aug. 31, 2020
Nov. 30, 2020
Feb. 28, 2021
May 31, 2021
Aug. 31, 2021
Nov. 30, 2021
Feb. 28, 2022
May 31, 2022
Aug. 31, 2022
Nov. 30, 2022
Feb. 28, 2023
May 31, 2023
Aug. 31, 2023
Nov. 30, 2023
Feb. 29, 2024
May 31, 2024
Aug. 31, 2024
Nov. 30, 2024
Feb. 28, 2025
May 31, 2025
Aug. 31, 2025
Nov. 30, 2025
Feb. 28, 2026
May 31, 2026
C000005534                                                                                  
Account Value [Line Items]                                                                                  
Accumulated Value $ 10,000 $ 10,346 $ 10,226 $ 10,672 $ 11,006 $ 11,306 $ 11,596 $ 11,727 $ 11,721 $ 11,866 $ 11,563 $ 11,962 $ 12,075 $ 12,493 $ 12,792 $ 12,680 $ 12,631 $ 13,673 $ 14,180 $ 14,710 $ 15,246 $ 15,606 $ 15,354 $ 14,823 $ 14,048 $ 13,640 $ 13,693 $ 13,752 $ 13,988 $ 14,347 $ 14,514 $ 15,340 $ 15,704 $ 16,317 $ 16,657 $ 16,739 $ 16,859 $ 17,595 $ 18,155 $ 18,877 $ 19,303
C000169940                                                                                  
Account Value [Line Items]                                                                                  
Accumulated Value 500,000 517,310 511,600 533,925 550,609 565,635 580,459 587,303 587,021 594,278 579,419 599,422 605,402 626,630 641,657 636,037 633,919 686,213 711,675 738,646 765,541 783,982 771,329 744,639 706,361 685,801 688,916 692,100 703,860 722,526 731,199 773,039 791,332 822,763 839,738 844,551 850,473 888,210 916,794 953,644 975,493
Bloomberg U.S. Aggregate Bond Index                                                                                  
Account Value [Line Items]                                                                                  
Accumulated Value 10,000 10,232 9,908 10,008 10,158 10,283 10,227 10,059 10,120 10,175 10,089 10,378 10,768 11,210 11,178 11,590 11,781 11,936 11,992 11,750 11,734 11,925 11,854 11,440 10,769 10,552 10,332 10,328 10,538 10,426 10,454 10,671 10,676 11,187 11,173 11,291 11,258 11,538 11,809 11,998 11,836
Bloomberg U.S. Aggregate Bond Index                                                                                  
Account Value [Line Items]                                                                                  
Accumulated Value 500,000 511,616 495,403 500,416 507,893 514,136 511,326 502,944 505,990 508,741 504,464 518,886 538,376 560,492 558,902 579,506 589,067 596,775 599,611 587,524 586,682 596,272 592,695 571,989 538,444 527,606 516,596 516,381 526,907 521,310 522,690 533,562 533,786 559,349 558,625 564,552 562,924 576,891 590,474 599,896 591,821
Morningstar Moderately Conservative Target Risk Index                                                                                  
Account Value [Line Items]                                                                                  
Accumulated Value 10,000 10,329 10,197 10,571 10,820 11,043 11,313 11,336 11,355 11,575 11,292 11,664 11,792 12,213 12,586 12,516 12,669 13,502 13,982 14,215 14,803 15,169 14,919 14,495 13,702 13,236 13,304 13,328 13,519 13,808 13,902 14,614 14,795 15,608 15,840 15,926 16,127 16,863 17,362 18,060 18,323
Morningstar Moderately Conservative Target Risk Index                                                                                  
Account Value [Line Items]                                                                                  
Accumulated Value $ 500,000 $ 516,435 $ 509,838 $ 528,568 $ 541,022 $ 552,163 $ 565,633 $ 566,784 $ 567,741 $ 578,736 $ 564,584 $ 583,199 $ 589,604 $ 610,644 $ 629,293 $ 625,779 $ 633,468 $ 675,104 $ 699,116 $ 710,746 $ 740,128 $ 758,468 $ 745,956 $ 724,732 $ 685,116 $ 661,810 $ 665,216 $ 666,379 $ 675,949 $ 690,419 $ 695,107 $ 730,706 $ 739,750 $ 780,406 $ 791,982 $ 796,298 $ 806,368 $ 843,128 $ 868,104 $ 903,019 $ 916,162