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Quarterly Financial Data (Unaudited) (Tables) | 12 Months Ended
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Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract] |
Quarterly Financial Data |
|  | Quarter ended |
|  | March 31 |  | June 30 |  |  |  | Sept. 30 |  |  |  | Dec. 31 |
|  | (in thousands, except per share amounts) |
2017 |  |  |  |  |  |  |  |  |  |  |  |  |
Revenues |  | $ | 882,664 |  |  | $ | 795,552 |  |  |  |  | $ | 795,513 |  |  |  |  | $ | 826,494 |  |
Gross profit |  | 159,346 |  |  | 130,553 |  |  |  |  | 139,966 |  |  |  |  | 142,866 |  |
Operating income |  | 53,492 |  |  | 22,938 |  |  |  | 29,799 |  |  |  |  | 23,712 |  |
Net income |  | 35,628 |  |  | 14,018 |  |  |  |  | 19,202 |  |  |  |  | 15,554 |  |
Basic net income per share(1) |  | 0.85 |  |  | 0.34 |  |  |  |  | 0.46 |  |  |  |  | 0.36 |  |
Diluted net income per share(1) |  | 0.85 |  |  | 0.33 |  |  |  |  | 0.46 |  |  |  |  | 0.36 |  |
2016 |  |  |  |  |  |  |  |  |  |  |  |  |
Revenues |  | $ | 802,408 |  |  | $ | 707,332 |  |  |  |  | $ | 702,538 |  |  |  |  | $ | 729,069 |  |
Gross profit |  | 150,016 |  |  | 113,259 |  |  |  |  | 117,796 |  |  |  |  | 110,539 |  |
Operating income |  | 53,043 |  |  | 16,023 |  |  |  |  | 22,773 |  |  |  |  | 14,467 |  |
Net income |  | 32,693 |  |  | 9,713 |  |  |  |  | 14,065 |  |  |  |  | 9,520 |  |
Basic net income per share(1) |  | 0.77 |  |  | 0.23 |  |  |  |  | 0.33 |  |  |  |  | 0.23 |  |
Diluted net income per share(1) |  | 0.77 |  |  | 0.23 |  |  |  |  | 0.33 |  |  |  |  | 0.23 |  |
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(1) | Adjusted to reflect the two-for-one split of our common stock effected on December 18, 2017 as a stock dividend.

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