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BASIS OF PRESENTATION - Recent Accounting Pronouncements (Details) - USD ($) $ in Thousands | 3 Months Ended |  |  |
--- | --- | --- | --- | ---
Mar. 31, 2019 | Dec. 31, 2018 | Jan. 01, 2018 | Jan. 01, 2016
Recent accounting pronouncements |  |  |  |
Equity investments with readily determinable fair values | $ 300 | $ 300 |  |
Accumulated other comprehensive income | (1,433) | (1,609) |  |
Retained earnings | 559,319 | 563,593 |  |
ASU 2016-01 |  |  |  |
Recent accounting pronouncements |  |  |  |
Equity investments that do not have readily determinable fair values |  |  |  | $ 20,100
Equity investments with readily determinable fair values |  |  |  | 600
ASU 2018-15 | Early Adoption |  |  |  |
Recent accounting pronouncements |  |  |  |
Capitalized implementation costs | 500 | $ 600 |  |
Amortization of implementation costs | $ 0 |  |  |
Adjustment | ASU 2016-01 |  |  |  |
Recent accounting pronouncements |  |  |  |
Accumulated other comprehensive income |  |  |  | (200)
Retained earnings |  |  |  | $ 200
Adjustment | ASU 2018-02 | Early Adoption |  |  |  |
Recent accounting pronouncements |  |  |  |
Accumulated other comprehensive income |  |  | $ (800) |
Retained earnings |  |  | 800 |
Valuation allowance |  |  | $ 800 |

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