The percentage of the number of Performance Units Granted as shares.

No definition available.

Name:	nafc_PercentageOfNumberOfPerformanceUnitsGrantedInShares
Namespace Prefix:	nafc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	nafc_ShareBasedCompensationDetailsLineItems
Namespace Prefix:	nafc_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5047-113901

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SAB TOPIC 14.F)

-URI http://asc.fasb.org/extlink&oid=27013229&loc=d3e301413-122809

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (h)(1)(i)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 14

-Section F

+ Details

Name:	us-gaap_AllocatedShareBasedCompensationExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(2)(iii)(1)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of shares under non-option equity instrument agreements that were cancelled as a result of occurrence of a terminating event.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(iv)(3)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsForfeitures
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Net number of non-option equity instruments granted to participants.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(iv)(1)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGranted
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

Share-Based Compensation (Details) (USD $) In Millions, except Share data, unless otherwise specified	6 Months Ended			0 Months Ended	3 Months Ended		6 Months Ended
	Jun. 15, 2013	Jun. 15, 2013 Performance Based Grants [Member] Long Term Incentive Plan LTIP [Member]	Jun. 15, 2013 Performance Based Grants [Member]	Dec. 29, 2012 Long Term Incentive Plan LTIP [Member] 2009 Plan [Member]	Jun. 15, 2013 Selling, General and Administrative Expenses [Member]	Jun. 16, 2012 Selling, General and Administrative Expenses [Member]	Jun. 15, 2013 Selling, General and Administrative Expenses [Member]	Jun. 16, 2012 Selling, General and Administrative Expenses [Member]	Jun. 15, 2013 2009 Plan [Member]	Jun. 15, 2013 Time Vesting Equity Units [Member]	Jun. 15, 2013 Performance Vesting Units [Member]	Jun. 15, 2013 Minimum [Member]	Jun. 15, 2013 Maximum [Member]
Share-Based Compensation (Details) [Line Items]
Allocated Share-based Compensation Expense					$ 0.7	$ 0.5	$ 1.2	$ 1.6
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years								3 years
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Forfeitures (in Shares)			(11,500)	101,739
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Granted (in Shares)		297,405	297,800
Percentage Of Number Of Performance Units Granted In Shares												0.00%	200.00%
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value (in Dollars per share)										$ 21.01	$ 20.83