Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Earnings Per Share [Abstract]
Net income	$ 11,420	$ 15,682	$ 14,341	$ 10,806	$ 12,948	$ 13,251	$ 11,130	$ 8,399	$ 53,376	$ 45,728	$ 44,158
Basic weighted average shares									52,924,398	54,045,841	54,809,319
Effect of dilutive stock options and restricted stock									525,356	435,643	559,697
Diluted weighted average shares									53,449,754	54,481,484	55,369,016
Basic (usd per share)	$ 0.22	$ 0.30	$ 0.27	$ 0.20	$ 0.24	$ 0.24	$ 0.21	$ 0.16	$ 1.01	$ 0.85	$ 0.81
Diluted (usd per share)	$ 0.21	$ 0.29	$ 0.27	$ 0.20	$ 0.24	$ 0.24	$ 0.20	$ 0.15	$ 1.00	$ 0.84	$ 0.80
Anti-dilutive shares (in shares)									469,603	146,548	32,436