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Benefit Plans (Allocation of Plan Assets) (Details) - USD ($) $ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2018 | Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | $ 214.5 | $ 239.5
Weighted average asset allocations | 100.00% | 100.00%
Level 2 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets |  | $ 0.0
Cash [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | $ 1.7 | 1.6
Cash [Member] | Level 1 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | $ 1.7 | $ 1.6
Equity Securities [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Weighted average asset allocations | 23.00% | 63.00%
Target allocation | 30.00% | 65.00%
International Mutual Funds [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | $ 17.7 | $ 15.5
International Mutual Funds [Member] | Level 1 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 17.7 | $ 15.5
International Mutual Funds [Member] | Level 2 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 0.0 |
International Mutual Funds [Member] | Level 3 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | $ 0.0 |
Debt Securities [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Weighted average asset allocations | 74.00% | 37.00%
Target allocation | 70.00% | 35.00%
Other [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Weighted average asset allocations | 3.00% | 0.00%
Target allocation | 0.00% |
Mutual Funds [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | $ 13.9 | $ 17.5
Mutual Funds [Member] | Level 1 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 13.9 | 17.5
Mutual Funds [Member] | Level 2 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 0.0 |
Mutual Funds [Member] | Level 3 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 0.0 |
Pension Plan Assets In The Fair Value Hierarchy [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 33.3 | 34.6
Pension Plan Assets In The Fair Value Hierarchy [Member] | Level 1 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 33.3 | 34.6
Pension Plan Assets In The Fair Value Hierarchy [Member] | Level 2 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 0.0 |
Pension plan assets measured at NAV [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | $ 181.2 | $ 204.9
Minimum [Member] | Equity Securities [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description | .27 |
Minimum [Member] | Debt Securities [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description | .67 |
Minimum [Member] | Other [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description | 0 |
Maximum [Member] | Equity Securities [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description | .33 |
Maximum [Member] | Debt Securities [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description | .73 |
Maximum [Member] | Other [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description | .03 |

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- Definition Amount of asset segregated and restricted to provide benefit under defined benefit plan. Asset includes, but is not limited to, stock, bond, other investment, earning from investment, and contribution by employer and employee. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(01) -URI http://asc.fasb.org/extlink&oid=108410482&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(01) -URI http://asc.fasb.org/extlink&oid=108410482&loc=d3e1928-114920 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(ii) -URI http://asc.fasb.org/extlink&oid=108410482&loc=d3e1928-114920 Reference 4: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 55 -Paragraph 17 -URI http://asc.fasb.org/extlink&oid=112275985&loc=d3e4179-114921 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=108410482&loc=d3e1928-114920 Reference 6: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(ii) -URI http://asc.fasb.org/extlink&oid=108410482&loc=d3e1928-114920 + Details
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- Definition Description of investment policy and strategy for defined benefit plan asset. Includes, but is not limited to, investment allocation decision and factor pertinent to understanding investment policy and strategy for plan asset. Factor includes, but is not limited to, investment goal, risk management practice, permitted and prohibited investment including use of derivative, diversification, and relationship between plan asset and obligation. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 55 -Paragraph 17 -URI http://asc.fasb.org/extlink&oid=112275985&loc=d3e4179-114921 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(i) -URI http://asc.fasb.org/extlink&oid=108410482&loc=d3e1928-114920 + Details
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- Definition Percentage of target investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 55 -Paragraph 17 -URI http://asc.fasb.org/extlink&oid=112275985&loc=d3e4179-114921 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(i) -URI http://asc.fasb.org/extlink&oid=108410482&loc=d3e1928-114920 + Details
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