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v3.3.1.900

Pension Plans and Other Postretirement Benefits (Details-4) $ in Thousands | 12 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2015 USD ($) concentration | Dec. 31, 2014 USD ($) | Dec. 31, 2013 USD ($)
Other postretirement benefits [Abstract] |  |  |  |
Fair value of plan assets |  | $ 330,886 | $ 327,500 |
Real Estate [Member] |  |  |  |
Other postretirement benefits [Abstract] |  |  |  |
Fair value of plan assets |  | $ 27,231 | $ 23,480 |
Pension Benefits [Member] |  |  |  |
Defined Benefit Plan, Information about Plan Assets [Abstract] |  |  |  |
Target Plan Asset Allocation |  | 100.00% |  |
Actual Plan Asset Allocation |  | 100.00% | 100.00% |
Other postretirement benefits [Abstract] |  |  |  |
Fair value of plan assets |  | $ 290,716 | $ 288,548 | $ 277,398
Pension Benefits [Member] | Plan Assets [Member] |  |  |  |
Concentration of Credit Risk [Abstract] |  |  |  |
Concentration risk, percentage |  | 10.00% |  |
Concentration risk, number of significant concentrations | concentration |  | 0 |  |
Pension Benefits [Member] | Equity Securities [Member] |  |  |  |
Defined Benefit Plan, Information about Plan Assets [Abstract] |  |  |  |
Target Plan Asset Allocation | [1] | 63.00% |  |
Actual Plan Asset Allocation |  | 63.00% | 62.00% |
Pension Benefits [Member] | United States Equity Securities [Member] |  |  |  |
Defined Benefit Plan, Information about Plan Assets [Abstract] |  |  |  |
Target Plan Asset Allocation |  | 45.50% |  |
Pension Benefits [Member] | Non-United States Equity Securities [Member] |  |  |  |
Defined Benefit Plan, Information about Plan Assets [Abstract] |  |  |  |
Target Plan Asset Allocation |  | 17.50% |  |
Pension Benefits [Member] | Fixed Income Securities [Member] |  |  |  |
Defined Benefit Plan, Information about Plan Assets [Abstract] |  |  |  |
Target Plan Asset Allocation |  | 30.00% |  |
Actual Plan Asset Allocation |  | 29.00% | 31.00% |
Pension Benefits [Member] | Real Estate [Member] |  |  |  |
Defined Benefit Plan, Information about Plan Assets [Abstract] |  |  |  |
Target Plan Asset Allocation |  | 7.00% |  |
Actual Plan Asset Allocation |  | 8.00% | 7.00% |
Postretirement Benefits [Member] |  |  |  |
Other postretirement benefits [Abstract] |  |  |  |
Fair value of plan assets |  | $ 40,170 | $ 38,952 | $ 37,602
Postretirement Benefits [Member] | Plan Assets [Member] |  |  |  |
Concentration of Credit Risk [Abstract] |  |  |  |
Concentration risk, percentage |  | 10.00% |  |
Concentration risk, number of significant concentrations | concentration |  | 0 |  |
Master Pension Trust [Member] |  |  |  |
Other postretirement benefits [Abstract] |  |  |  |
Fair value of plan assets |  | $ 34,100 | $ 32,800 |
[1] | Target allocations for equity securities are broken out as follows: 45.5 % United States equity, 17.5 % non-United States equity .

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