Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Reconciliation of the component parts of earnings per share [Abstract]
Net income	$ 10,947	$ 10,409
Weighted average common shares (in shares)	95,879	95,365
Stock Options (in shares)	108	47
Weighted average common shares including potential dilutive shares (in shares)	95,987	95,412
Basic EPS (in dollars per share)	$ 0.114	$ 0.109
Diluted EPS (in dollars per share)	$ 0.114	$ 0.109
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average number of antidilutive stock options excluded from diluted earnings per share (in shares)	553	1,600