v3.8.0.1

ACQUISITIONS Table 2 - Certain Financial Information Related to the Navigator Acquisition (Details) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended
--- | --- | ---
Dec. 31, 2017 | Sep. 30, 2017 | Jun. 30, 2017 | Mar. 31, 2017 | Dec. 31, 2016 | Sep. 30, 2016 | Jun. 30, 2016 | Mar. 31, 2016 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |  |  |
Revenues | $ 450,535 | $ 440,566 | $ 435,488 | $ 487,430 | $ 471,757 | $ 441,418 | $ 437,804 | $ 405,703 | $ 1,814,019 | $ 1,756,682 | $ 2,084,040
Operating income (loss) | $ 74,018 | $ 91,717 | $ 73,404 | $ 97,139 | $ 85,373 | $ 87,954 | $ 91,217 | $ 94,565 | 336,278 | $ 359,109 | $ 390,704
Navigator Acquisition [Member] |  |  |  |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  | 42,620 |  |
Operating income (loss) |  |  |  |  |  |  |  |  | (1,724) |  |
Business acquisition, transaction costs |  |  |  |  |  |  |  |  | 14,079 |  |
Navigator Acquisition [Member] | General and administrative expense [Member] |  |  |  |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |  |  |
Business acquisition, transaction costs |  |  |  |  |  |  |  |  | 10,391 |  |
Navigator Acquisition [Member] | Interest expense, net [Member] |  |  |  |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |  |  |
Business acquisition, transaction costs |  |  |  |  |  |  |  |  | $ 3,688 |  |

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