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Retirement Plans (Tables) | 12 Months Ended
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Dec. 31, 2017
Retirement Benefits [Abstract] |
Reconciliation of Balances of Pension Benefit Obligation and Fair Value of Plan Assets | A reconciliation of the beginning and ending balances of the pension benefit obligation and fair value of plan assets and the funded status of the plan is as follows (in millions):
|  | Year Ended December 31, |
|  | 2017 |  |  | 2016 |
Change in pension benefit obligation: |  |  |  |  |  |  |  |
Benefit obligation at beginning of year |  | $ | 261.3 |  |  | $ | 261.8 |
Service cost |  |  | 1.7 |  |  |  | 1.5 |
Interest cost |  |  | 10.0 |  |  |  | 10.8 |
Net actuarial loss |  |  | 11.5 |  |  |  | 1.8 |
Benefits paid |  |  | (13.1 | ) |  |  | (14.6 | )
Benefit obligation at end of year |  | $ | 271.4 |  |  | $ | 261.3 |
Change in plan assets: |  |  |  |  |  |  |  |
Fair value of plan assets at beginning of year |  | $ | 207.8 |  |  | $ | 207.5 |
Actual return on plan assets |  |  | 24.7 |  |  |  | 14.9 |
Contributions by the company |  |  | — |  |  |  | — |
Benefits paid |  |  | (13.1 | ) |  |  | (14.6 | )
Fair value of plan assets at end of year |  | $ | 219.4 |  |  | $ | 207.8 |
Funded status of the plan (underfunded) |  | $ | (52.0 | ) |  | $ | (53.5 | )
Amounts recognized in the consolidated balance sheet consist of: |  |  |  |  |  |  |  |
Noncurrent liabilities - accrued benefit liability |  | $ | (52.0 | ) |  | $ | (53.5 | )
Accumulated other comprehensive loss - net actuarial loss |  |  | 63.7 |  |  |  | 67.9 |
Net amount included in retained earnings |  | $ | 11.7 |  |  | $ | 14.4 |
Components of Net Periodic Pension Benefit Cost and Other Changes in Plan Assets and Obligations Recognized in Earnings and Other Comprehensive Earnings | The components of the net periodic pension benefit cost for the plan and other changes in plan assets and obligations recognized in earnings and other comprehensive earnings consist of the following (in millions):
|  | Year Ended December 31, |
|  | 2017 |  |  | 2016 |  |  | 2015 |
Net periodic pension cost: |  |  |  |  |  |  |  |  |  |  |  |
Service cost |  | $ | 1.7 |  |  | $ | 1.5 |  |  | $ | 1.1 |
Interest cost on benefit obligation |  |  | 10.0 |  |  |  | 10.8 |  |  |  | 10.8 |
Expected return on plan assets |  |  | (14.0 | ) |  |  | (14.6 | ) |  |  | (15.3 | )
Amortization of net loss |  |  | 5.0 |  |  |  | 5.3 |  |  |  | 6.2 |
Net periodic benefit cost |  |  | 2.7 |  |  |  | 3.0 |  |  |  | 2.8 |
Other changes in plan assets and obligations recognized in other comprehensive earnings: |  |  |  |  |  |  |  |  |  |  |  |
Net loss incurred |  |  | 0.8 |  |  |  | 1.4 |  |  |  | 2.9 |
Amortization of net loss |  |  | (5.0 | ) |  |  | (5.3 | ) |  |  | (6.2 | )
Total recognized in other comprehensive loss |  |  | (4.2 | ) |  |  | (3.9 | ) |  |  | (3.3 | )
Total recognized in net periodic pension cost and other comprehensive loss |  | $ | (1.5 | ) |  | $ | (0.9 | ) |  | $ | (0.5 | )
Estimated amortization for the following year: |  |  |  |  |  |  |  |  |  |  |  |
Amortization of net loss |  | $ | 5.0 |  |  | $ | 5.5 |  |  | $ | 5.9 |
Weighted Average Assumptions of Pension Benefit Obligation and Net Periodic Pension Benefit Cost | The following weighted average assumptions were used at December 31 in determining the plan’s pension benefit obligation:
|  | December 31, |
|  | 2017 |  |  | 2016 |
Discount rate |  |  | 3.50 | % |  |  | 4.00 | %
Weighted average expected long-term rate of return on plan assets |  |  | 7.00 | % |  |  | 7.25 | %
The following weighted average assumptions were used at January 1 in determining the plan’s net periodic pension benefit cost:
|  | Year Ended December 31, |
|  | 2017 |  |  | 2016 |  |  | 2015 |
Discount rate |  |  | 4.00 | % |  |  | 4.25 | % |  |  | 4.00 | %
Weighted average expected long-term rate of return on plan assets |  |  | 7.00 | % |  |  | 7.25 | % |  |  | 7.25 | %
Schedule of Benefit Payments Expected to be Paid by Plan | The following benefit payments are expected to be paid by the plan (in millions):
2018 |  | $ | 13.5 |
2019 |  |  | 14.3 |
2020 |  |  | 14.3 |
2021 |  |  | 15.1 |
2022 |  |  | 15.4 |
Years 2023 to 2027 |  |  | 81.0 |
Summary of Plans Weighted Average Asset Allocations | The following is a summary of the plan’s weighted average asset allocations at December 31 by asset category:
|  | December 31, |
Asset Category |  | 2017 |  |  | 2016 |
Equity securities |  |  | 61.0 | % |  |  | 61.0 | %
Debt securities |  |  | 32.0 | % |  |  | 33.0 | %
Real estate |  |  | 7.0 | % |  |  | 6.0 | %
Total |  |  | 100.0 | % |  |  | 100.0 | %
Summary of Plan's Assets Carried at Fair Value | The following is a summary of the plan’s assets carried at fair value as of December 31 by level within the fair value hierarchy (in millions):
|  | December 31, |
Fair Value Hierarchy |  | 2017 |  |  | 2016 |
Level 1 |  | $ | — |  |  | $ | — |
Level 2 |  |  | 107.5 |  |  |  | 108.1 |
Level 3 |  |  | 111.9 |  |  |  | 99.7 |
Total fair value |  | $ | 219.4 |  |  | $ | 207.8 |
Reconciliation of Beginning and Ending Balances for Level 3 Assets of Plan Measured at Fair Value | The following is a reconciliation of the beginning and ending balances for the Level 3 assets of the plan measured at fair value (in millions):
|  | Year Ended December 31, |
|  | 2017 |  |  | 2016 |
Fair value at January 1 |  | $ | 99.7 |  |  | $ | 100.7 |
Settlements |  |  | — |  |  |  | (7.5 | )
Unrealized gains |  |  | 12.2 |  |  |  | 6.5 |
Fair value at December 31 |  | $ | 111.9 |  |  | $ | 99.7 |

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- Definition Tabular disclosure of assets measured at fair value measured on a recurring or nonrecurring basis. Includes, but is not limited to, fair value measurements recorded and the reasons for the measurements, level within the fair value hierarchy in which the fair value measurements are categorized and transfers between levels 1 and 2. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19190-110258 + Details
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- Definition Tabular disclosure of the assumptions used to determine for pension plans and/or other employee benefit plans the benefit obligation and net benefit cost, including assumed discount rates, rate increase in compensation increase, and expected long-term rates of return on plan assets. + 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) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 + Details
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