Long-Term Incentive Plan (Equity-Based Incentive Compensation Expense) (Details) - USD ($) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| Long Term Incentive Plan [Line Items] | |||
| Allocation of LTIP expense on Consolidated Statements of Income | $ 32,053 | $ 20,641 | $ 19,358 |
| G&A Expense [Member] | |||
| Long Term Incentive Plan [Line Items] | |||
| Allocation of LTIP expense on Consolidated Statements of Income | 31,788 | 20,463 | 19,204 |
| Operating Expenses [Member] | |||
| Long Term Incentive Plan [Line Items] | |||
| Allocation of LTIP expense on Consolidated Statements of Income | 265 | 178 | 154 |
| Performance Shares [Member] | |||
| Long Term Incentive Plan [Line Items] | |||
| Allocation of LTIP expense on Consolidated Statements of Income | 28,728 | 17,823 | 17,106 |
| Time-Based Awards [Member] | |||
| Long Term Incentive Plan [Line Items] | |||
| Allocation of LTIP expense on Consolidated Statements of Income | $ 3,325 | $ 2,818 | $ 2,252 |