Consolidated Statements of Changes in Shareholders' Equity (Unaudited) (USD $) In Thousands, unless otherwise specified	Common Stock [Member]	Capital in Excess of Par Value [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total
Balance at Dec. 31, 2011	$ 7,807	$ 56,395	$ 81,797	$ 6,830	$ 152,829
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	0	0	8,449	0	8,449
Other comprehensive loss	0	0	0	291	291
Stock options exercised	3	42	0	0	45
Equity based compensation	26	388	0	0	414
Cash dividends declared	0	0	(3,604)	0	(3,604)
Balance at Jun. 30, 2012	7,836	56,825	86,642	7,121	158,424
Balance at Dec. 31, 2012	7,847	57,211	90,591	7,597	163,246
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	0	0	8,361	0	8,361
Other comprehensive loss	0	0	0	(5,447)	(5,447)
Stock options exercised	6	96	0	0	102
Equity based compensation	19	274	0	0	293
Cash dividends declared	0	0	(3,619)	0	(3,619)
Balance at Jun. 30, 2013	$ 7,872	$ 57,581	$ 95,333	$ 2,150	$ 162,936