Fair Value Measurements - Schedule of Assets at Fair Value on Nonrecurring Basis (Details) - Fair Value, Measurements, Nonrecurring - USD ($) $ in Thousands |
Jun. 30, 2018 |
Dec. 31, 2017 |
|---|---|---|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Long-lived assets held and used | $ 4,818 | $ 28,312 |
| Long-lived assets held for sale | 0 | 42,142 |
| Level 1 | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Long-lived assets held and used | 0 | 0 |
| Long-lived assets held for sale | 0 | 0 |
| Level 2 | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Long-lived assets held and used | 0 | 0 |
| Long-lived assets held for sale | 0 | 0 |
| Level 3 | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Long-lived assets held and used | 4,818 | 28,312 |
| Long-lived assets held for sale | $ 0 | $ 42,142 |