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Retirement Plans (Weighted-Average Expense Assumptions) (Details) | 12 Months Ended
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Dec. 31, 2015 | Dec. 31, 2014 | Dec. 31, 2013
Expected return on plan assets |  | 6.37% |  |
Retirement Income Plan [Member] |  |  |  |
Discount rate |  | 4.29% | 5.16% | 4.66%
Expected return on plan assets |  | 6.27% | 6.92% | 7.40%
Rate of compensation increase |  | 4.00% | 4.00% | 4.00%
Discount rate used to value the liability |  | 4.69% | 4.29% |
Pension Plan Service Cost [Member] |  |  |  |
Discount rate | [1] | 4.52% |  |
Pension Plan Interest Cost [Member] |  |  |  |
Discount rate | [1] | 4.02% |  |
[1] | Our latest measurement date was December 31, 2015 and we increased our expected return on plan assets to 6.37%, reflecting the current interest rate environment. When determining the most appropriate discount rate to be used in the valuation, we consider, among other factors, our expected payout patterns of the plans' obligations as well as our investment strategy and we ultimately select the rate that we believe best represents our estimate of the inherent interest rate at which our pension and post-retirement life benefits can be effectively settled. Effective January 1, 2016, the approach used to calculate the service and interest components of net periodic benefit cost for benefit plans was changed to provide a more precise measurement of service and interest costs. Historically, we calculated these service and interest components utilizing a single weighted-average discount rate derived from the yield curve used to measure the benefit obligation at the beginning of the period. Going forward, we have elected to utilize an approach that discounts the individual expected cash flows using the applicable spot rates derived from the yield curve over the projected cash flow period. We will account for this change prospectively as a change in accounting estimate. The weighted average discount rates used to determine 2016 service and interest costs are 4.52% and 4.02%, respectively.

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- Definition The interest rate used to adjust for the time value of money for 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 (k)(1) -URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920 + Details
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- Definition The interest rate used to adjust for the time value of money. + 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 (k)(1) -URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920 + Details
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- Definition An assumption as to the rate of return on plan assets reflecting the average rate of earnings expected on the funds invested or to be invested to provide for the benefits included in the benefit obligation. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Expected Long-Term Rate of Return on Plan Assets -URI http://asc.fasb.org/extlink&oid=6512046 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (k)(3) -URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920 + Details
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- Definition Expected rate of compensation increases (for pay-related plans). + 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 (k)(2) -URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920 + Details
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