Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Earnings Per Share [Abstract]
Net income	$ 13,251	$ 12,440	$ 32,780	$ 33,625
Basic weighted average shares (in shares)	54,209,942	54,905,288	54,160,649	54,851,911
Effect of dilutive stock options and restricted stock (in shares)	369,648	578,755	462,514	571,383
Diluted weighted average shares (in shares)	54,579,590	55,484,043	54,623,163	55,423,294
Basic (usd per share)	$ 0.24	$ 0.23	$ 0.61	$ 0.61
Diluted (usd per share)	$ 0.24	$ 0.22	$ 0.60	$ 0.61
Anti-dilutive shares (in shares)	138,661	29,132	135,971	22,676