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]
Outstanding stock options (in shares)		0	0	0	0
Distributed earnings allocated to common stock		$ 4,299	$ 4,299	$ 12,888	$ 12,796
Undistributed earnings allocated to common stock		9,499	10,466	29,748	29,733
Net earnings allocated to common stock		13,798	14,765	42,636	42,529
Net earnings allocated to participating securities		130	182	433	544
Net income allocated to common stock and participating securities		$ 13,928	$ 14,947	$ 43,069	$ 43,073
Weighted average shares outstanding for basic earnings per common share	[1]	26,164,646	26,262,864	26,211,630	26,497,500
Dilutive effect of stock compensation (in shares)		0	0	0	0
Weighted average shares outstanding for diluted earnings per common share	[1]	26,164,646	26,262,864	26,211,630	26,497,500
Basic earnings per common share (in dollars per share)	[1]	$ 0.53	$ 0.56	$ 1.63	$ 1.61
Diluted earnings per common share (in dollars per share)	[1]	$ 0.53	$ 0.56	$ 1.63	$ 1.61

[1] *The computation of per common share data and shares outstanding gives retrospective recognition to a 10% stock dividend declared on July 22, 2015 and issued on August 14, 2015.