Consolidated Statement of Changes in Stockholders' Equity (USD $)	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]	Total
Balance at Dec. 31, 2011	$ 3,133,000	$ 15,313,000	$ 63,337,000	$ 4,949,000	$ (5,264,000)	$ 81,468,000
Balance (in shares) at Dec. 31, 2011	3,132,866
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income			14,215,000			14,215,000
Net other comprehensive loss				(318,000)		(318,000)
Stock dividend	28,000	1,110,000	(1,138,000)			0
Stock dividend (in shares)	28,458
Purchase of treasury stock					(1,348,000)	(1,348,000)
Restricted stock and Board of Director awards		(156,000)			14,000	(142,000)
Restricted stock vesting		201,000				201,000
Cash dividend reinvestment paid from treasury stock						0
Cash dividends			(4,601,000)			(4,601,000)
Balance at Dec. 31, 2012	3,161,000	16,468,000	71,813,000	4,631,000	(6,598,000)	89,475,000
Balance (in shares) at Dec. 31, 2012	3,161,324
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income			13,375,000			13,375,000
Net other comprehensive loss				(5,856,000)		(5,856,000)
Stock dividend	145,000	7,022,000	(7,167,000)			0
Stock dividend (in shares)	144,193
Purchase of treasury stock					(1,483,000)	(1,483,000)
Restricted stock and Board of Director awards		(149,000)			34,000	(115,000)
Restricted stock vesting		218,000				218,000
Forfeited restricted stock		2,000			(2,000)
Cash dividend reinvestment paid from treasury stock		1,000	(138,000)		137,000	0
Cash dividends			(3,558,000)			(3,558,000)
Balance at Dec. 31, 2013	3,306,000	23,562,000	74,325,000	(1,225,000)	(7,912,000)	92,056,000
Balance (in shares) at Dec. 31, 2013	3,305,517
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income			13,385,000			13,385,000
Net other comprehensive loss				1,992,000		1,992,000
Stock dividend	29,000	1,568,000	(1,597,000)			0
Stock dividend (in shares)	29,719
Purchase of treasury stock					(814,000)	(814,000)
Restricted stock and Board of Director awards		(189,000)			19,000	(170,000)
Restricted stock vesting		200,000				200,000
Cash dividend reinvestment paid from treasury stock		9,000	(480,000)		471,000	0
Cash dividends			(6,121,000)			(6,121,000)
Balance at Dec. 31, 2014	$ 3,335,000	$ 25,150,000	$ 79,512,000	$ 767,000	$ (8,236,000)	$ 100,528,000
Balance (in shares) at Dec. 31, 2014	3,335,236