Earnings Per Share (Tables)

12 Months Ended

Dec. 31, 2018

Earnings Per Share [Abstract]

Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]

The reconciliations of the denominators of the basic and diluted earnings per share computations are as follows (in thousands):

	Years Ended December 31,
	2018	2017	2016
Weighted average common shares outstanding—basic	89,215	89,056	88,896
Dilutive effect of potential common shares	132	120	158
Weighted average common shares outstanding—diluted	89,347	89,176	89,054