Revenue - Contract Estimates (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Revenue
Accrued sales incentives	$ 1.4	$ 1.8
Other accrued deductions	$ 1.4	$ 2.0

Carrying value as of the balance sheet date of obligations incurred through that date and payable for sales incentives. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

No definition available.

Name:	wch_AccruedSalesIncentivesCurrent
Namespace Prefix:	wch_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant