Quarterly Financial Information (Unaudited) - (Details) - USD ($) $ / shares in Units, $ in Thousands |
3 Months Ended | 12 Months Ended | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2016 |
Sep. 30, 2016 |
Jun. 30, 2016 |
Mar. 31, 2016 |
Dec. 31, 2015 |
Sep. 30, 2015 |
Jun. 30, 2015 |
Mar. 31, 2015 |
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
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| Quarterly Financial Information Disclosure [Abstract] | |||||||||||||
| Revenues | $ 794,954 | $ 768,982 | $ 789,353 | $ 854,427 | $ 821,199 | $ 767,694 | $ 769,049 | $ 821,814 | $ 3,207,716 | $ 3,179,756 | $ 2,695,033 | ||
| Gross Profit | [1] | 339,599 | 332,487 | 352,576 | 374,268 | 344,144 | 331,628 | 346,110 | 363,478 | ||||
| Earnings Before Income Taxes | 32,288 | 45,282 | 61,124 | 79,728 | 34,380 | 36,556 | 64,354 | 77,830 | 218,422 | 213,120 | 121,704 | ||
| Net Earnings | $ 21,631 | $ 29,464 | $ 38,501 | $ 49,687 | $ 21,726 | $ 24,194 | $ 40,546 | $ 49,243 | $ 139,283 | $ 135,709 | $ 78,233 | ||
| Earnings Per Share (in dollars per share) | $ 0.30 | $ 0.41 | $ 0.53 | $ 0.68 | $ 0.30 | $ 0.33 | $ 0.56 | $ 0.68 | $ 1.93 | $ 1.87 | $ 1.08 | ||
| Earnings Per Share Assuming Dilution (in dollars per share) | $ 0.30 | $ 0.40 | $ 0.53 | $ 0.68 | $ 0.30 | $ 0.33 | $ 0.56 | $ 0.68 | $ 1.91 | $ 1.86 | $ 1.08 | ||
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