Pension and Other Postretirement Benefits Change in benefit obligation (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Benefit obligation	$ 238,319	$ 174,954
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Benefit obligation	134,652	149,263	134,289
Service cost	2,527	1,790	1,668
Interest cost	5,681	5,512	5,728
Medicare Part D	0	210
Actuarial loss (gain)	(24,170)	11,725
Acquisition	6,544	0
Benefits paid	(5,193)	(4,263)
Curtailment/special termination benefits	0	0	0
Pension Plans, Defined Benefit [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Benefit obligation	238,319	174,954	164,565
Service cost	4,735	2,802	3,133
Interest cost	8,908	6,871	6,976
Medicare Part D	0	0
Actuarial loss (gain)	(21,539)	8,611
Acquisition	82,988	0
Benefits paid	(11,727)	(7,895)
Curtailment/special termination benefits	$ 0	$ 0	$ (1,147)

Amount of gain (loss) related to change in benefit obligation resulting from changes in actuarial assumptions, for example, but not limited to, interest, mortality, employee turnover, salary, and temporary deviation from the substantive plan.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 30

-Glossary Gain or Loss

-URI http://asc.fasb.org/extlink&oid=6514294

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (a)(4)

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 60

-Glossary Gain or Loss

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- Definition

1) For defined benefit pension plans, the benefit obligation is the projected benefit obligation, which is the actuarial present value as of a date of all benefits attributed by the pension benefit formula to employee service rendered prior to that date. 2) For other postretirement defined benefit plans, the benefit obligation is the accumulated postretirement benefit obligation, which is the actuarial present value of benefits attributed to employee service rendered to a particular date.

+ 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 (a)

-URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e1928-114920

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Projected Benefit Obligation

-URI http://asc.fasb.org/extlink&oid=6522206

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Accumulated Postretirement Benefit Obligation

-URI http://asc.fasb.org/extlink&oid=6503904

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- Definition

The amount of payments made for which participants are entitled under a pension plan, including pension benefits, death benefits, and benefits due on termination of employment. Also includes payments made under a postretirement benefit plan, including prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services. This item represents a periodic decrease to the plan obligations and a decrease to plan assets.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Postretirement Benefits

-URI http://asc.fasb.org/extlink&oid=6521376

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 60

-Section 50

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=6414203&loc=d3e39716-114964

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 30

-Glossary Benefits

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-Publisher FASB

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-Topic 715

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-Publisher FASB

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-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (a)(6)

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- Definition

The amount of increase in the benefit obligation attributed to business combinations.

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- Definition

Amount of the period's gross receipts received from the prescription drug subsidy, which is to be used in the roll forward of the accumulated postretirement benefit obligation of an applicable postretirement benefit plan.

+ References

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-Publisher FASB

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- Definition

The increase in a defined benefit pension plan's projected benefit obligation or a defined benefit postretirement plan's accumulated postretirement benefit obligation due to the passage of time.

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- Definition

The actuarial present value of benefits attributed by the pension benefit formula to services rendered by employees during the period. The portion of the expected postretirement benefit obligation attributed to employee service during the period. The service cost component is a portion of the benefit obligation and is unaffected by the funded status of the plan.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

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-Subparagraph (h)(1)

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-Publisher FASB

-Name Accounting Standards Codification

-Glossary Service Cost (Component of Net Periodic Pension Cost)

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- Definition

The amount of increase related to special termination benefits offered to and accepted by employees in connection with their termination of employment that are only offered for a short period of time. A situation involving termination benefits may also involve a curtailment.

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