| Label | Element | Value |
|---|---|---|
| Institutional Shares | Repurchase Agreements [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Total Investments | oef_PctOfTotalInv | 48.70% |
| Institutional Shares | U.S. Government Agencies [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Total Investments | oef_PctOfTotalInv | 33.50% |
| Institutional Shares | U.S. Treasury Notes [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Total Investments | oef_PctOfTotalInv | 9.40% |
| Institutional Shares | U.S. Treasury Bills [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Total Investments | oef_PctOfTotalInv | 8.40% |