Earnings Per Share (Tables)

3 Months Ended

Mar. 31, 2018

Schedule of Weighted Average Number of Shares [Table Text Block]

Average shares used in computing the basic and diluted earnings per share are as follows:



	Three Months Ended
	March 31, 2018	March 31, 2017
Basic computation	49,416,230	48,385,738
Dilutive effect of:
Performance share awards (1)	67,622	117,658

Diluted computation	49,483,852	48,503,396

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(1) Performance share awards are included in diluted weighted average number of shares outstanding based upon what would be issued if the end of the most recent reporting period was the end of the term of the award. The dilutive share calculation for 2018 excludes 34,913 shares under outstanding performance share awards because the inclusion of these awards would have been antidilutive under the treasury stock method.