Share-based Compensation, Stock Options, Activity [Table Text Block] |
| | Shares | | Weighted Average Exercise Price | | Weighted Average Remaining Contractual Term (years) | | Aggregate Intrinsic Value | | | | | | | | | (In Thousands) | Year Ended December 31, 2018: | | | | | | | | | | | | | | | | | Outstanding at beginning of year | | | 1,666,834 | | | $ | 10.68 | | | | 5.5 | | | $ | 51,377 | | Granted | | | 42,250 | | | | 37.21 | | | | 9.6 | | | | - | | Exercised | | | (414,336 | ) | | | 5.73 | | | | 2.8 | | | | 10,832 | | Forfeited | | | (56,000 | ) | | | 15.40 | | | | 6.2 | | | | 912 | | Outstanding at end of year | | | 1,238,748 | | | $ | 13.02 | | | | 5.2 | | | $ | 23,355 | | | | | | | | | | | | | | | | | | | Exercisable at December 31, 2018 | | | 510,100 | | | $ | 7.08 | | | | 3.5 | | | $ | 12,645 | | | | | | | | | | | | | | | | | | | Year Ended December 31, 2017: | | | | | | | | | | | | | | | | | Outstanding at beginning of year | | | 2,026,334 | | | $ | 9.00 | | | | 6.2 | | | $ | 57,636 | | Granted | | | 58,000 | | | | 37.59 | | | | 9.1 | | | | 227 | | Exercised | | | (385,500 | ) | | | 4.96 | | | | 4.0 | | | | 14,087 | | Forfeited | | | (32,000 | ) | | | 21.96 | | | | 8.1 | | | | 625 | | Outstanding at end of year | | | 1,666,834 | | | $ | 10.68 | | | | 5.5 | | | $ | 51,377 | | | | | | | | | | | | | | | | | | | Exercisable at December 31, 2017 | | | 808,236 | | | $ | 5.22 | | | | 3.9 | | | $ | 29,321 | | | | | | | | | | | | | | | | | | | Year Ended December 31, 2016: | | | | | | | | | | | | | | | | | Outstanding at beginning of year | | | 2,498,834 | | | $ | 6.66 | | | | 6.3 | | | $ | 42,746 | | Granted | | | 241,000 | | | | 20.15 | | | | 9.1 | | | | 4,166 | | Exercised | | | (682,500 | ) | | | 4.28 | | | | 3.9 | | | | 22,629 | | Forfeited | | | (31,000 | ) | | | 11.04 | | | | 6.8 | | | | 818 | | Outstanding at end of year | | | 2,026,334 | | | $ | 9.00 | | | | 6.2 | | | $ | 57,636 | | | | | | | | | | | | | | | | | | | Exercisable at December 31, 2016 | | | 928,536 | | | $ | 5.08 | | | | 4.8 | | | $ | 30,051 | |
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Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity [Table Text Block] |
Range of Exercise Price | | Shares | | Weighted Average Exercise Price | | Weighted Average Remaining Contractual Term (years) | | Aggregate Intrinsic Value | | | | | | | | | (In Thousands) | $ | 4.17 | | | | 27,500 | | | $ | 4.17 | | | | 0.8 | | | $ | 762 | | | 5.00 | | | | 244,000 | | | | 5.00 | | | | 2.6 | | | | 6,556 | | | 5.50 | | | | 120,000 | | | | 5.50 | | | | 4.2 | | | | 3,164 | | | 6.92 | | | | 45,000 | | | | 6.92 | | | | 5.0 | | | | 1,123 | | | 15.74 | | | | 21,600 | | | | 15.74 | | | | 6.1 | | | | 348 | | | 18.57 | | | | 52,000 | | | | 18.57 | | | | 4.5 | | | | 692 | | | | | | | 510,100 | | | $ | 7.08 | | | | 3.5 | | | $ | 12,645 | |
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