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Benefit Plans (Summary Of Performance Shares and Performance Units Activity) (Details) - USD ($) $ in Millions | 3 Months Ended
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Mar. 31, 2016 | Mar. 31, 2015
Performance Shares [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward] |  |
Nonvested, January 1 (in shares/awards) | 144,215 | 144,424
Granted (in shares/awards) | 33,776 | 45,403
Vested (in shares/awards) | (49,093) | (45,612)
Forfeited (in shares/awards) | (615) | 0
Nonvested, March 31 (in shares/awards) | 128,283 | 144,215
Performance Units [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward] |  |
Nonvested, January 1 (in shares/awards) | 58,206 | 63,665
Granted (in shares/awards) | 11,959 | 17,837
Vested (in shares/awards) | (21,380) | (22,845)
Forfeited (in shares/awards) | (382) | (93)
Nonvested, March 31 (in shares/awards) | 48,403 | 58,564
2013 Grant [Member] | Performance Shares [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward] |  |
Vested (in shares/awards) | (49,093) |
Vested percentage of the target | 165.00% |
Aggregate payout value | $ 5.1 |
Payout - cash | $ 2.9 |
Payout - common stock shares issued (in shares) | 11,204 |
2013 Grant [Member] | Performance Units [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward] |  |
Vested (in shares/awards) | (21,380) |
Vested percentage of the target | 165.00% |
Aggregate payout value | $ 1.7 |
Payout - cash | $ 1.7 |
2012 Grant [Member] | Performance Shares [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward] |  |
Vested (in shares/awards) |  | (45,612)
Vested percentage of the target |  | 167.50%
Aggregate payout value |  | $ 5.1
Payout - cash |  | $ 3.2
Payout - common stock shares issued (in shares) |  | 10,975
2012 Grant [Member] | Performance Units [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward] |  |
Vested (in shares/awards) |  | (22,845)
Vested percentage of the target |  | 167.50%
Aggregate payout value |  | $ 1.6
Payout - cash |  | $ 1.6

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- Definition Costs and payments related to employee benefits and equity-based compensation, such as pension expense and contributions, other postretirement benefits expense and payments, stock or unit options expense, and amortization of restricted stock or unit. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585 + Details
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- Definition Aggregate cash paid by the entity during the period to settle equity instruments granted under equity-based payment arrangements. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (k) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1)(iv)(3) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2)(iii)(1) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2)(i)-(ii) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. + References No definition available. + Details
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- Definition The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2)(iii)(2) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Number of share instruments newly issued under a share-based compensation plan. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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