Earnings per Share Earnings per Share (Tables)

12 Months Ended

Dec. 31, 2016

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

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

The following table summarizes the dilutive effect of restricted shares and options to purchase common stock:

	Year ended December 31,
	2016	2015	2014
Weighted average common shares—basic	45,407,316	45,123,626	44,881,925
Dilutive effect of restricted share awards	—	—	245,828
Dilutive effect of stock options	—	—	141,656
Weighted average common shares—diluted	45,407,316	45,123,626	45,269,409