Your standard homeowners insurance policy covers theft, regardless of whether items are stolen outside or inside your house. Theft coverage is part of your homeowners insurance’s personal property coverage.
Insurance companies usually reimburse you in two ways. If you have "replacement cost" coverage, your insurer will help you purchase the item at today's pricing. On the other hand, if you have "actual cash value" coverage, your insurer will take depreciation into account and only pay what the stolen item would have been worth if you were to sell it in today’s market.