CONSOLIDATED STATEMENTS OF INCOME (Unaudited) (Parenthetical) (USD $)	3 Months Ended
Mar. 28, 2014	Mar. 29, 2013
Income Statement [Abstract]
Limited partnership interest value	$ 1,000	$ 1,000

The per unit price of limited partnership interest, which represents the book value of each interest and has been arbitrarily determined.

No definition available.

Name:	jnfc_LimitedPartnershipInterestValuePerUnit
Namespace Prefix:	jnfc_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration