Pension Plans and Other Postretirement Benefits (Details-6) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014
Change in plan assets [Roll Forward]
Fair value of plan assets at beginning of year	$ 327,500
Fair value of plan assets at end of year	330,886	$ 327,500
Real Estate [Member]
Change in plan assets [Roll Forward]
Fair value of plan assets at beginning of year	23,480
Fair value of plan assets at end of year	27,231	23,480
Insurance Continuance Fund [Member]
Change in plan assets [Roll Forward]
Fair value of plan assets at beginning of year	1,518
Fair value of plan assets at end of year	1,518	1,518
Fixed Rate Fund [Member]
Change in plan assets [Roll Forward]
Fair value of plan assets at beginning of year	4,446
Fair value of plan assets at end of year	4,208	4,446
Level 3 [Member]
Change in plan assets [Roll Forward]
Fair value of plan assets at beginning of year	29,444
Fair value of plan assets at end of year	32,957	29,444
Level 3 [Member] \| Real Estate [Member]
Change in plan assets [Roll Forward]
Fair value of plan assets at beginning of year	23,480	19,628
Actual return on plan assets still held	2,749	1,561
Purchases, sales, and settlements	1,002	2,291
Transfers in and/or out of Level 3	0	0
Fair value of plan assets at end of year	27,231	23,480
Level 3 [Member] \| Insurance Continuance Fund [Member]
Change in plan assets [Roll Forward]
Fair value of plan assets at beginning of year	1,518	1,428
Actual return on plan assets still held	46	44
Purchases, sales, and settlements	(46)	46
Transfers in and/or out of Level 3	0	0
Fair value of plan assets at end of year	1,518	1,518
Level 3 [Member] \| Fixed Rate Fund [Member]
Change in plan assets [Roll Forward]
Fair value of plan assets at beginning of year	4,446	0
Actual return on plan assets still held	103	54
Purchases, sales, and settlements	(341)	4,392
Transfers in and/or out of Level 3	0	0
Fair value of plan assets at end of year	$ 4,208	$ 4,446

Actual return on plan assets, separately identifying the amount related to assets still held at the reporting date.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(iv)(02)(A)
-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 5
-Subparagraph (c)(iv)(02)(A)
-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e2446-114920

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

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- Definition

Assets, usually stocks, bonds, and other investments, that have been segregated and restricted (usually in a trust) to provide benefits, at their fair value as of the measurement date. Plan assets include amounts contributed by the employer (and by employees for a contributory plan) and amounts earned from investing the contributions, less benefits paid. If a plan has liabilities other than for benefits, those non-benefit obligations may be considered as reductions of plan assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 30
-Section 35
-Paragraph 50
-URI http://asc.fasb.org/extlink&oid=49178875&loc=d3e12355-114930

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920

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- Definition

Amount of increase (decrease) in plan assets from purchases, sales and settlement of plan obligations.

+ 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 (d)(iv)(02)(B)
-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 5
-Subparagraph (c)(iv)(02)(B)
-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e2446-114920

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- Definition

Transfers in and out of Level 3. For example, transfers due to changes in the observability of significant inputs.

+ 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 (d)(iv)(02)(C)
-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920

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-Name Accounting Standards Codification
-Topic 715
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-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e2446-114920

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