Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Earnings Per Share [Abstract]
Net income	$ 14,717	$ 15,682	$ 38,728	$ 41,956
Basic weighted average shares (in shares)	52,566,619	52,891,879	52,586,429	52,942,571
Effect of dilutive stock options and restricted stock (in shares)	447,650	502,452	516,979	524,452
Diluted weighted average shares (in shares)	53,014,269	53,394,331	53,103,408	53,467,023
Basic (usd per share)	$ 0.28	$ 0.30	$ 0.74	$ 0.79
Diluted (usd per share)	$ 0.28	$ 0.29	$ 0.73	$ 0.78
Anti-dilutive shares (in shares)	842,631	551,940	795,678	512,823