Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Numerator [Abstract]
Net income	$ 12,312	$ 11,222	$ 35,480	$ 34,562
Basic earnings per share [Abstract]
Weighted average shares (in shares)	17,554,000	17,440,000	17,532,000	17,420,000
Diluted earnings per share [Abstract]
Effect of dilutive stock options and restricted stock grants (in shares)	15,000	51,000	16,000	52,000
Adjusted weighted average shares (in shares)	17,569,000	17,491,000	17,548,000	17,472,000
Earnings per share [Abstract]
Basic earnings per share (in dollars per share)	$ 0.70	$ 0.64	$ 2.02	$ 1.98
Diluted earnings per share (in dollars per share)	$ 0.70	$ 0.64	$ 2.02	$ 1.98
Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Options excluded from diluted calculations (in shares)	0	0	15,730	0
Weighted average price for anti dilutive securities (in dollars per share)	$ 35.409	$ 0	$ 35.409	$ 0