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Retirement Plans (Quantitative Disclosures of Retirement Income Plan's Invested Assets that are Measured at Fair Value on a Recurring Basis) (Details) - Retirement Income Plan [Member] - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Total Assets	$ 249,700	$ 253,452	$ 225,817
Fair Value [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	249,781	253,521
Fair Value [Member] | Alternative Investments [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	6,458	10,392
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	152,462	230,535
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Alternative Investments [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	0	0
Significant Other Observable Inputs (Level 2) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	90,861	12,594
Significant Other Observable Inputs (Level 2) [Member] | Alternative Investments [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	0	0
Significant Unobservable Inputs (Level 3) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	6,458	10,392
Significant Unobservable Inputs (Level 3) [Member] | Alternative Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	6,458	10,392	$ 12,159
Significant Unobservable Inputs (Level 3) [Member] | Alternative Investments [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	6,458	10,392
Global Asset Allocation Fund [Member] | Fair Value [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	33,565	27,782
Global Asset Allocation Fund [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	33,565	27,782
Global Asset Allocation Fund [Member] | Significant Other Observable Inputs (Level 2) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	0	0
Global Asset Allocation Fund [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	0	0
Extended Duration Fixed Income [Member] | Fair Value [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	117,297	120,532
Extended Duration Fixed Income [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	117,297	120,532
Extended Duration Fixed Income [Member] | Significant Other Observable Inputs (Level 2) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	0	0
Extended Duration Fixed Income [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	0	0
Total Long Duration Fixed Income [Member] | Fair Value [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	150,862	148,314
Total Long Duration Fixed Income [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	150,862	148,314
Total Long Duration Fixed Income [Member] | Significant Other Observable Inputs (Level 2) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	0	0
Total Long Duration Fixed Income [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	0	0
International equity [Member] | Fair Value [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	42,603	16,852
International equity [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	0	5,438
International equity [Member] | Significant Other Observable Inputs (Level 2) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	42,603	11,414
International equity [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	0	0
US Global Equity [Member] | Fair Value [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	46,840	47,719
US Global Equity [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	0	47,719
US Global Equity [Member] | Significant Other Observable Inputs (Level 2) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	46,840	0
US Global Equity [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	0	0
Global Equity [Member] | Fair Value [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	89,443	64,571
Global Equity [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	0	53,157
Global Equity [Member] | Significant Other Observable Inputs (Level 2) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	89,443	11,414
Global Equity [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	0	0
Global Asset Allocation [Member] | Fair Value [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		27,842
Global Asset Allocation [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		27,842
Global Asset Allocation [Member] | Significant Other Observable Inputs (Level 2) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		0
Global Asset Allocation [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		0
Equity Long Short Hedge [Member] | Fair Value [Member] | Alternative Investments [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		41
Equity Long Short Hedge [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Alternative Investments [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		0
Equity Long Short Hedge [Member] | Significant Other Observable Inputs (Level 2) [Member] | Alternative Investments [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		0
Equity Long Short Hedge [Member] | Significant Unobservable Inputs (Level 3) [Member] | Alternative Investments [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		41
Private Equity [Member] | Fair Value [Member] | Alternative Investments [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	4,852	8,136
Private Equity [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Alternative Investments [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	0	0
Private Equity [Member] | Significant Other Observable Inputs (Level 2) [Member] | Alternative Investments [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	0	0
Private Equity [Member] | Significant Unobservable Inputs (Level 3) [Member] | Alternative Investments [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	4,852	8,136
Real Estate Strategy [Member] | Fair Value [Member] | Alternative Investments [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	1,606	2,215
Real Estate Strategy [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Alternative Investments [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	0	0
Real Estate Strategy [Member] | Significant Other Observable Inputs (Level 2) [Member] | Alternative Investments [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	0	0
Real Estate Strategy [Member] | Significant Unobservable Inputs (Level 3) [Member] | Alternative Investments [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	1,606	2,215
Short-term Investments [Member] | Fair Value [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	1,600	1,222
Short-term Investments [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	1,600	1,222
Short-term Investments [Member] | Significant Other Observable Inputs (Level 2) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	0	0
Short-term Investments [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	0	0
Deposit Administration Contracts [Member] | Fair Value [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	1,418	1,180
Deposit Administration Contracts [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	0	0
Deposit Administration Contracts [Member] | Significant Other Observable Inputs (Level 2) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	1,418	1,180
Deposit Administration Contracts [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	0	0
Cash And Short Term Investments [Member] | Fair Value [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	3,018	2,402
Cash And Short Term Investments [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	1,600	1,222
Cash And Short Term Investments [Member] | Significant Other Observable Inputs (Level 2) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	1,418	1,180
Cash And Short Term Investments [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	$ 0	$ 0

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+ 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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