v3.19.1

Long-Term Incentive Plan (Equity-Based Incentive Compensation Expense) (Details) - USD ($) $ in Thousands | 3 Months Ended
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Mar. 31, 2019 | Mar. 31, 2018
Share-based Compensation Arrangements by Share-based Payment Award [Line Items] |  |
Allocation of LTIP expense on consolidated statements of income | $ 4,914 | $ 6,632
G&A Expense [Member] |  |
Share-based Compensation Arrangements by Share-based Payment Award [Line Items] |  |
Allocation of LTIP expense on consolidated statements of income | 4,871 | 6,577
Operating Expenses [Member] |  |
Share-based Compensation Arrangements by Share-based Payment Award [Line Items] |  |
Allocation of LTIP expense on consolidated statements of income | 43 | 55
Performance Based Awards [Member] |  |
Share-based Compensation Arrangements by Share-based Payment Award [Line Items] |  |
Allocation of LTIP expense on consolidated statements of income | 3,644 | 5,924
Time-Based Awards [Member] |  |
Share-based Compensation Arrangements by Share-based Payment Award [Line Items] |  |
Allocation of LTIP expense on consolidated statements of income | $ 1,270 | $ 708

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