Fair Value - Additional Information (Detail) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
Jun. 27, 2025	Dec. 31, 2024
Fair Value Disclosures [Abstract]
Fair value of level III, assets	$ 0	$ 0

Assets categorized as level III during the reporting period.

No definition available.

Name:	ck0000815917_UnobservableInputsAssetsFairValueDisclosure
Namespace Prefix:	ck0000815917_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration