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Benefit Plans (Fair Values Of Nonvested Performance Shares And Performance Units) (Details) | 12 Months Ended
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Dec. 31, 2018 $ / shares shares
Performance Shares [Member] |
Defined Benefit Plan Disclosure [Line Items] |
Nonvested, December 31 (in shares/awards) | 203,188
Performance Units [Member] |
Defined Benefit Plan Disclosure [Line Items] |
Nonvested, December 31 (in shares/awards) | 57,761
2018 Grant [Member] | Performance Shares [Member] |
Defined Benefit Plan Disclosure [Line Items] |
Nonvested, December 31 (in shares/awards) | 70,483
Estimated payout percentage based on performance criteria | 85.00%
Fair values of each nonvested award (in dollars per share) | $ / shares | $ 35.91
2018 Grant [Member] | Performance Units [Member] |
Defined Benefit Plan Disclosure [Line Items] |
Nonvested, December 31 (in shares/awards) | 19,196
Estimated payout percentage based on performance criteria | 85.00%
Fair values of each nonvested award (in dollars per share) | $ / shares | $ 35.91
2017 Grant [Member] | Performance Shares [Member] |
Defined Benefit Plan Disclosure [Line Items] |
Nonvested, December 31 (in shares/awards) | 65,350
Estimated payout percentage based on performance criteria | 85.00%
Fair values of each nonvested award (in dollars per share) | $ / shares | $ 35.91
2017 Grant [Member] | Performance Units [Member] |
Defined Benefit Plan Disclosure [Line Items] |
Nonvested, December 31 (in shares/awards) | 18,062
Estimated payout percentage based on performance criteria | 85.00%
Fair values of each nonvested award (in dollars per share) | $ / shares | $ 35.91
2016 Grant [Member] | Performance Shares [Member] |
Defined Benefit Plan Disclosure [Line Items] |
Nonvested, December 31 (in shares/awards) | 67,355
Estimated payout percentage based on performance criteria | 143.00%
Fair values of each nonvested award (in dollars per share) | $ / shares | $ 60.42
2016 Grant [Member] | Performance Units [Member] |
Defined Benefit Plan Disclosure [Line Items] |
Nonvested, December 31 (in shares/awards) | 20,503
Estimated payout percentage based on performance criteria | 143.00%
Fair values of each nonvested award (in dollars per share) | $ / shares | $ 60.42

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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + 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=96867065&loc=d3e5070-113901 + Details
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