Earnings Per Share (Tables)

3 Months Ended

Mar. 31, 2019

Earnings Per Share [Abstract]

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, 2019	March 31, 2018
Basic computation	50,380,839	49,416,230
Dilutive effect of:
Performance share awards (1)	348,525	67,622
Diluted computation	50,729,364	49,483,852

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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.