Inventories - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
Jun. 30, 2026	Jun. 30, 2025
Inventory Disclosure [Abstract]
Unrealized gains (losses) included in inventory balance	$ (71,100)	$ 94,800
Premium on metals position	$ 11,245	$ 35,295

Inventory unrealized gains losses resulting from market value and cost of physical inventory excluding collectible coin inventory.

No definition available.

Name:	gold_InventoryUnrealizedGainsLossesResultingFromMarketValueAndCostOfPhysicalInventoryExcludingCollectibleCoinInventory
Namespace Prefix:	gold_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration