v3.20.1

Long-Term Incentive Plan (Total Non-Vested Unit Awards) (Details) - USD ($) $ in Millions | Dec. 31, 2019 | Dec. 31, 2018
--- | --- | ---
Long Term Incentive Plan [Line Items] |  |
Non-vested units (in shares) | 640,220 | 501,403
Adjustment to Unit Awards in Anticipation of Achieving Above- Target Financial Results (in shares) | 0 |
Total Unit Award Accrual (in shares) | 640,220 |
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount | $ 21.8 |
Performance Shares [Member] |  |
Long Term Incentive Plan [Line Items] |  |
Non-vested units (in shares) | 379,904 | 390,015
Time-Based Awards [Member] |  |
Long Term Incentive Plan [Line Items] |  |
Non-vested units (in shares) | 260,316 | 111,388
Two Thousand Eighteen Awards [Member] | Performance Shares [Member] |  |
Long Term Incentive Plan [Line Items] |  |
Non-vested units (in shares) | 205,568 |
Adjustment to Unit Awards in Anticipation of Achieving Above- Target Financial Results (in shares) | 0 |
Total Unit Award Accrual (in shares) | 205,568 |
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount | $ 4.9 |
Two Thousand Nineteen Awards [Member] | Performance Shares [Member] |  |
Long Term Incentive Plan [Line Items] |  |
Non-vested units (in shares) | 174,336 |
Adjustment to Unit Awards in Anticipation of Achieving Above- Target Financial Results (in shares) | 0 |
Total Unit Award Accrual (in shares) | 174,336 |
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount | $ 7.3 |
Retention Awards Vesting 2020 [Member] | Time-Based Awards [Member] |  |
Long Term Incentive Plan [Line Items] |  |
Non-vested units (in shares) | 76,820 |
Adjustment to Unit Awards in Anticipation of Achieving Above- Target Financial Results (in shares) | 0 |
Total Unit Award Accrual (in shares) | 76,820 |
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount | $ 1.9 |
Retention Awards Vesting 2021 [Member] | Time-Based Awards [Member] |  |
Long Term Incentive Plan [Line Items] |  |
Non-vested units (in shares) | 180,162 |
Adjustment to Unit Awards in Anticipation of Achieving Above- Target Financial Results (in shares) | 0 |
Total Unit Award Accrual (in shares) | 180,162 |
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount | $ 7.5 |
Retention Awards Vesting 2022 [Member] | Time-Based Awards [Member] |  |
Long Term Incentive Plan [Line Items] |  |
Non-vested units (in shares) | 3,334 |
Adjustment to Unit Awards in Anticipation of Achieving Above- Target Financial Results (in shares) | 0 |
Total Unit Award Accrual (in shares) | 3,334 |
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount | $ 0.2 |

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- Definition Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Total Unit Award Accrual Number + References No definition available. + Details
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- Definition Amount of cost not yet recognized for nonvested award under share-based payment arrangement. + 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 (i) -URI http://asc.fasb.org/extlink&oid=116856206&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://fasb.org/us-gaap/role/ref/legacyRef -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=116856206&loc=d3e5070-113901 + Details
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