Consolidated Statements Of Changes In Shareholders' Equity (USD $) In Thousands	Common Stock [Member]	Capital in Excess of Par Value [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Deferred Compensation Arrangements [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total
Balance at Dec. 31, 2009	$ 67	$ 36,278	$ 63,165	$ (17,798)	$ 6,246	$ 2,667	$ 90,625
Net income	0	0	15,461	0	0	0	15,461
Dividends paid ($1.12 per share)	0	0	(6,901)	0	0	0	(6,901)
Sale of treasury stock	0	0	0	10	0	0	10
Distribution of stock under deferred compensation arrangements	0	0	0	455	(455)	0	0
Shares issued under stock plans, net of excess tax benefit	0	(7)	0	63	207	0	263
Share-based compensation expense	0	101	0	0	0	0	101
Dividend reinvestment plan	0	(24)	0	434	352	0	762
Other comprehensive income (loss)	0	0	0	0	0	(990)	(990)
Balance at Dec. 31, 2010	67	36,348	71,725	(16,836)	6,350	1,677	99,331
Net income	0	0	14,620	0	0	0	14,620
Dividends paid ($1.12 per share)	0	0	(6,952)	0	0	0	(6,952)
Sale of treasury stock	0	1	0	13	0	0	14
Distribution of stock under deferred compensation arrangements	0	0	0	432	(432)	0	0
Shares issued under stock plans, net of excess tax benefit	0	19	0	273	(76)	0	216
Share-based compensation expense	0	110	0	0	54	0	164
Dividend reinvestment plan	0	66	0	301	352	0	719
Other comprehensive income (loss)	0	0	0	0	0	1,425	1,425
Balance at Dec. 31, 2011	67	36,544	79,393	(15,817)	6,248	3,102	109,537
Net income	0	0	15,194	0	0	0	15,194
Dividends paid ($1.12 per share)	0	0	(7,007)	0	0	0	(7,007)
Sale of treasury stock	0	2	0	16	0	0	18
Distribution of stock under deferred compensation arrangements	0	0	0	386	(386)	0	0
Shares issued under stock plans, net of excess tax benefit	0	41	0	380	90	0	511
Share-based compensation expense	0	72	0	0	100	0	172
Dividend reinvestment plan	0	83	0	249	351	0	683
Other comprehensive income (loss)	0	0	0	0	0	(887)	(887)
Balance at Dec. 31, 2012	$ 67	$ 36,742	$ 87,580	$ (14,786)	$ 6,403	$ 2,215	$ 118,221