Pension and Other Postretirement Plans (Components of Net Periodic Benefit Costs) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Pension Plans [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Interest cost	$ 958	$ 873	$ 928
Service cost	168	190	174
Expected return on plan assets	(1,278)	(1,134)	(1,070)
Amortization of prior service cost	4	4	4
Amortization of net loss (gain)	422	812	786
Net periodic benefit cost	274	745	822
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract]
Net (gain) loss	1,888	(3,921)
Amortization of prior service cost	(4)	(4)	(4)
Amortization of net loss (gain)	(422)	(812)	(786)
Total recognized in other comprehensive income	1,462	(4,737)
Total recognized in net periodic benefit cost and other comprehensive income	1,736	(3,992)
Chairman and President Non-Qualified Defined Benefit Plans [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Interest cost	1,003	801	912
Service cost	294	177	168
Amortization of prior service cost	59	59	59
Amortization of net loss (gain)	1,294	1,173	1,142
Net periodic benefit cost	2,650	2,210	2,281
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract]
Net (gain) loss	4,960	(1,652)
Amortization of prior service cost	(59)	(59)	(59)
Amortization of net loss (gain)	(1,294)	(1,173)	(1,142)
Total recognized in other comprehensive income	3,607	(2,884)
Total recognized in net periodic benefit cost and other comprehensive income	6,257	(674)
Defined Benefit Postretirement Healthcare Plans [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Interest cost	111	117	129
Amortization of prior service cost	103	103	103
Amortization of net loss (gain)	(4)	33	41
Net periodic benefit cost	210	253	273
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract]
Net (gain) loss	107	(827)
Amortization of prior service cost	(103)	(103)	(103)
Amortization of net loss (gain)	4	(33)	(41)
Total recognized in other comprehensive income	8	(963)
Total recognized in net periodic benefit cost and other comprehensive income	$ 218	$ (710)

Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income, Total, Net of Tax

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- Definition

The amount of gains or losses recognized in net periodic benefit cost.

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- Definition

The amount of the prior service cost or credit recognized in net periodic benefit cost relating to benefit changes attributable to plan participants' prior service pursuant to a plan amendment or a plan initiation.

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- Definition

Amount before tax, after reclassification adjustments, of actuarial gain (loss) that has not been recognized in the income statement.

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- Definition

An amount calculated as a basis for determining the extent of delayed recognition of the effects of changes in the fair value of assets. The expected return on plan assets is determined based on the expected long-term rate of return on plan assets and the market-related value of plan assets.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 30

-Glossary Expected Return on Plan Assets

-URI http://asc.fasb.org/extlink&oid=6512136

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 60

-Glossary Expected Return on Plan Assets

-URI http://asc.fasb.org/extlink&oid=6512171

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (h)(3)

-URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e1928-114920

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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 total amount of net periodic benefit cost for defined benefit plans for the period. Periodic benefit costs include the following components: service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) due to settlements or curtailments.

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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

-Section 50

-Paragraph 1

-Subparagraph (h)(1)

-URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e1928-114920

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

-Publisher FASB

-Name Accounting Standards Codification

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

-URI http://asc.fasb.org/extlink&oid=6525008

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e1928-114920

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- Definition

Amount after tax of reclassification adjustment from accumulated other comprehensive income (loss) for actuarial gain (loss) related to pension and other postretirement benefit plans.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 220

-SubTopic 10

-Section 45

-Paragraph 11

-URI http://asc.fasb.org/extlink&oid=36458714&loc=d3e637-108580

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-Name Accounting Standards Codification

-Topic 220

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