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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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- 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 + Details
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