Accounting Policies - Revenue Recognition (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Revenue Recognition
External freight billed to customers included in revenue	$ 12.3	$ 9.5	$ 34.0	$ 26.0

Represents fees charged to customers for the delivery, generally by postal or freight service providers, of product or goods purchased.

No definition available.

Name:	uslm_ShippingAndHandlingRevenues
Namespace Prefix:	uslm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration