Employee Benefits (Assumptions) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Pension Plan [Member]
Assumptions Used to Determine Benefit Obligations [Abstract]
Discount rate	4.00%	4.50%
Rate of compensation increase	3.50%	3.75%
Assumptions Used to Determine Net Periodic Benefit Cost [Abstract]
Discount rate	4.50%	5.50%	6.00%
Expected long-term rate of return on plan assets	8.00%	8.25%	8.25%
Rate of compensation increase	3.75%	4.00%	4.00%
Postretirement Benefit Plan [Member]
Assumptions Used to Determine Benefit Obligations [Abstract]
Discount rate	4.00%	4.50%
Assumptions Used to Determine Net Periodic Benefit Cost [Abstract]
Discount rate	4.50%	5.50%	6.00%
Effect of One-Percentage Point Change in Assumed Health Care Cost Trend Rates [Abstract]
Effect of 1% increase on the net periodic postretirement health care benefit cost	1,127
Effect of 1% decrease on the net periodic postretirement health care benefit cost	(876)
Effect of 1% increase on the accumulated postretirement benefit obligation	8,375
Effect of 1% decrease on the accumulated postretirement benefit obligation	(7,899)
Health Care Benefits [Member]
Assumed Health Care Cost Trend Rates [Abstract]
Health care cost trend rates assumed for next year	10.00%	10.00%
Rate to which the health care trend rate is assumed to decline (ultimate trend rate)	5.25%	5.25%
Dental Claims [Member]
Assumed Health Care Cost Trend Rates [Abstract]
Health care cost trend rates assumed for next year	5.25%	5.25%

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The interest rate used to adjust for the time value of money for the plan.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 5

-Subparagraph j

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (k)(1)

-URI http://asc.fasb.org/extlink&oid=21915506&loc=d3e1928-114920

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- Definition

Expected rate of compensation increases (for pay-related plans).

+ References

+ Details

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- Definition

The interest rate used to adjust for the time value of money.

+ References

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- Definition

An assumption as to the rate of return on plan assets reflecting the average rate of earnings expected on the funds invested or to be invested to provide for the benefits included in the benefit obligation.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (k)(3)

-URI http://asc.fasb.org/extlink&oid=21915506&loc=d3e1928-114920

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 87

-Paragraph 264

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 5

-Subparagraph j

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 30

-Glossary Expected Long-Term Rate of Return on Plan Assets

-URI http://asc.fasb.org/extlink&oid=6512013

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- Definition

Expected rate of compensation increases (for pay-related plans).

+ References

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- Definition

Amount of effect of a one-percentage-point decrease in the assumed health care cost trend rates on the accumulated postretirement benefit obligation for health care benefits.

+ References

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- Definition

Amount of effect of a one-percentage-point decrease in the assumed health care cost trend rates on the aggregate of the service and interest cost components of net periodic postretirement health care benefit costs.

+ References

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- Definition

The effect of a one-percentage-point increase in the assumed health care cost trend rates on the accumulated postretirement benefit obligation for health care benefits.

+ References

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- Definition

The effect of a one-percentage-point increase in the assumed health care cost trend rates on the aggregate of the service and interest cost components of net periodic postretirement health care benefit costs.

+ References

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- Definition

The assumed health care cost trend rate for the next year used to measure the expected cost of benefits covered by the plan (gross eligible charges). This is based upon the annual rate of change in the cost of health care benefits currently provided by the postretirement benefit plan, due to factors other than changes in the composition of the plan population by age and dependency status.

+ References

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- Definition

The ultimate trend rate for health care costs.

+ References

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