LONG-TERM DEBT, Lease Commitments (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2012 number
Future cash payments for capital leases [Abstract]
2013	10,156
2014	7,685
2015	5,074
2016	5,136
2017	5,164
Thereafter	56,591
Total Minimum Lease Payments	89,806
Less amounts representing interest	(45,548)
Present Value of Net minimum lease payments	44,258
Building [Member]
Leases, Capital [Abstract]
Terms of capital lease (in years)	30
Renewal options under capital lease	5
Number of renewal options exercised under capital lease	3
Number of additional renewal options under capital lease	2
Extended additional term of capital lease (in years)	10
Number of years in renewal period	five
Year the capital lease was entered into	1984
Amendment date	2010
Renewal option year	2015
Land and Building [Member]
Leases, Capital [Abstract]
Terms of capital lease (in years)	20
Renewal options under capital lease	10
Number of additional renewal options under capital lease	3
Year the capital lease was entered into	2007
Year operation transferred	2009

Capital lease amendment date

No definition available.

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- Definition

The date at which the capital lease was entered into

+ References

No definition available.

+ Details

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- Definition

The additional term (in years) under an existing capital lease agreement entered into by the entity, if the additional renewal options are exercised.

+ References

No definition available.

+ Details

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- Definition

The number of additional renewal options remaining under an existing capital lease agreement entered into by the entity.

+ References

No definition available.

+ Details

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- Definition

The number of renewal options exercised by the the entity under an existing capital lease agreement.

+ References

No definition available.

+ Details

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- Definition

No authoritative reference available.

+ References

No definition available.

+ Details

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- Definition

Number of renewal options that were available under an existing capital lease agreement entered into by the entity.

+ References

No definition available.

+ Details

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- Definition

The year in which three of the five year renewal options begin and are exercised.

+ References

No definition available.

+ Details

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- Definition

Terms, in years, under an existing capital lease agreement entered into by the entity.

+ References

No definition available.

+ Details

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- Definition

Year in which NPC transferred operations to the facilities.

+ References

No definition available.

+ Details

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- Definition

Amount of minimum lease payments for capital leases.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6455398&loc=d3e45280-112737

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 13

-Paragraph 16

-Subparagraph a(ii)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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- Definition

Amount of minimum lease payments maturing in the next fiscal year following the latest fiscal year for capital leases.

+ References

+ Details

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- Definition

Amount of minimum lease payments maturing in the forth fiscal year following the latest fiscal year for capital leases.

+ References

+ Details

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- Definition

Amount of minimum lease payments maturing in the third fiscal year following the latest fiscal year for capital leases.

+ References

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- Definition

Amount of minimum lease payments maturing in the second fiscal year following the latest fiscal year for capital leases.

+ References

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- Definition

Amount of minimum lease payments maturing after the fifth fiscal year following the latest fiscal year for capital leases.

+ References

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- Definition

Amount necessary to reduce net minimum lease payments to present value for capital leases.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 13

-Paragraph 7

-Subparagraph d

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 30

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 13

-Paragraph 10

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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- Definition

Present value of minimum lease payments for capital leases net of executory costs, including amounts paid by the lessee to the lessor for insurance, maintenance and taxes.

+ References

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- Definition

Amount of required minimum rental payments maturing in the fifth fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 13

-Paragraph 16

-Subparagraph b(i)

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-SubTopic 20

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-Paragraph 2

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6453985&loc=d3e41502-112717

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