The following table illustrates our computations of basic and diluted net earnings per common share ($ in thousands, except per share figures): | | | | | | | | | | | | | | | | | | Three months ended | | Nine months ended | | September 30, | | September 30, | | 2016 | | 2015 | | 2016 | | 2015 | Net earnings | $ | 2,753 |
| | $ | 15,737 |
| | $ | 21,476 |
| | $ | 40,384 |
| Average basic shares outstanding | 11,018 |
| | 11,321 |
| | 11,022 |
| | 11,385 |
| Basic net earnings per share | $ | 0.25 |
| | $ | 1.39 |
| | $ | 1.95 |
| | $ | 3.55 |
| | | | | | | | | Average basic shares outstanding | 11,018 |
| | 11,321 |
| | 11,022 |
| | 11,385 |
| Restricted stock not vested | 27 |
| | 18 |
| | 24 |
| | 16 |
| Dilutive effect of Performance Share Plan | 39 |
| | 45 |
| | 59 |
| | 73 |
| Average diluted shares outstanding | 11,084 |
| | 11,383 |
| | 11,105 |
| | 11,474 |
| Diluted net earnings per share | $ | 0.25 |
| | $ | 1.38 |
| | $ | 1.93 |
| | $ | 3.52 |
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