v3.20.1

Long-Term Incentive Plan (Weighted-Average Grant Date Fair Values) (Details) - $ / shares | 12 Months Ended
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Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Long Term Incentive Plan [Line Items] |  |  |
Units granted (in shares) | 377,865 |  |
Weighted-Average Grant Date Fair Value (in dollars per share) | $ 63.27 |  |
Performance Shares [Member] |  |  |
Long Term Incentive Plan [Line Items] |  |  |
Units granted (in shares) | 182,834 | 218,923 | 189,544
Weighted-Average Grant Date Fair Value (in dollars per share) | $ 63.65 | $ 73.80 | $ 82.34
Time-Based Awards [Member] |  |  |
Long Term Incentive Plan [Line Items] |  |  |
Units granted (in shares) | 195,031 | 83,564 | 30,604
Weighted-Average Grant Date Fair Value (in dollars per share) | $ 62.91 | $ 71.03 | $ 79.10

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- Definition Long Term Incentive Plan [Line Items] + References No definition available. + 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://fasb.org/us-gaap/role/ref/legacyRef -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=116856206&loc=d3e5070-113901 + Details
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- Definition The weighted average fair value at grant date for nonvested equity-based awards issued 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://fasb.org/us-gaap/role/ref/legacyRef -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=116856206&loc=d3e5070-113901 + Details
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