Earnings Per Share (Tables)

3 Months Ended

Mar. 31, 2018

Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]

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

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

	Three Months Ended March 31,
	2018	2017
Weighted-average common shares outstanding—basic and diluted	89,160	89,003