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Fair Value Measurements - (Narrative) (Details) - USD ($) $ in Thousands | 3 Months Ended |
--- | --- | ---
Mar. 31, 2021 | Mar. 31, 2020 | Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Contingent consideration arrangement | $ 6,000 |  |
Contingent consideration, gain (loss) due to change in value |  | $ 200 |
Asset retirement obligation capitalized | 483 | $ 381 |
Level 3 |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Contingent consideration arrangement | 6,000 |  | $ 6,200
Asset retirement obligation capitalized | 500 |  |
Prepaid Expenses and Other Current Assets |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Contingent consideration arrangement | 1,300 |  |
Other Noncurrent Assets |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Contingent consideration arrangement | $ 4,700 |  |

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