Earnings per Share Earnings per Share (Tables)

6 Months Ended

Jun. 30, 2018

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 stock units and options to purchase common stock for the three and six months ended June 30, 2018 and 2017:

	Three months ended June 30,		Six months ended June 30,
	2018	2017	2018	2017
Weighted average common shares—basic	45,920,307	45,717,697	45,850,137	45,644,096
Dilutive effect of restricted stock units	176,658	162,153	267,620	222,996
Dilutive effect of stock options	103,792	42,566	97,290	48,595
Weighted average common shares—diluted	46,200,757	45,922,416	46,215,047	45,915,687

In November 2015, the Company announced its Board of Directors had authorized the Company to purchase its common stock up to $50 million in the aggregate.  During the second quarter of 2018, the Company executed its first activity under its stock purchase program, purchasing 100,947 shares of its outstanding common stock for approximately $2.9 million.