Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings Per Share [Abstract]
Net income	$ 12,536	$ 14,085	$ 11,691	$ 4,260	$ 15,770	$ 14,717	$ 13,794	$ 10,217	$ 42,572	$ 54,498	$ 53,376
Basic weighted average shares									52,284,616	52,572,496	52,924,398
Effect of dilutive stock options and restricted stock									383,323	506,238	525,356
Diluted weighted average shares									52,667,939	53,078,734	53,449,754
Basic (usd per share)	$ 0.24	$ 0.27	$ 0.22	$ 0.08	$ 0.30	$ 0.28	$ 0.26	$ 0.19	$ 0.81	$ 1.04	$ 1.01
Diluted (usd per share)	$ 0.24	$ 0.27	$ 0.22	$ 0.08	$ 0.30	$ 0.28	$ 0.26	$ 0.19	$ 0.81	$ 1.03	$ 1.00
Anti-dilutive shares (in shares)									1,920,313	785,825	469,603