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Recent Accounting Pronouncements - Narrative (Details) - USD ($) $ in Thousands | Jun. 30, 2018 | Jan. 01, 2018 | Dec. 31, 2017
--- | --- | --- | ---
Revenue, Initial Application Period Cumulative Effect Transition [Line Items] |  |  |
Retained earnings | $ 306,375 | $ 274,836 | $ 274,562
Accumulated Other Comprehensive Income (Loss), Net of Tax | 6,340 |  | $ 4,366
Accounting Standards Update 2018-02 |  |  |
Revenue, Initial Application Period Cumulative Effect Transition [Line Items] |  |  |
Retained earnings | 350 |  |
Accumulated Other Comprehensive Income (Loss), Net of Tax | 350 |  |
Difference between Revenue Guidance in Effect before and after Topic 606 | Accounting Standards Update 2014-09 |  |  |
Revenue, Initial Application Period Cumulative Effect Transition [Line Items] |  |  |
Retained earnings | $ 893 | $ 274 |

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