Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Reconciliation of the component parts of earnings per share [Abstract]
Net income	$ 10,409	$ 10,715
Weighted average common shares (in shares)	95,365	94,947
Stock Options (in shares)	47	127
Weighted average common shares including potential dilutive shares (in shares)	95,412	95,074
Basic EPS (in dollars per share)	$ 0.109	$ 0.113
Diluted EPS (in dollars per share)	$ 0.109	$ 0.113
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)	1,600	1,400