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	12,088	0	12,088
Other comprehensive loss	0	0	0	1,849	1,849
Stock options exercised	7	111	0	0	118
Equity based compensation	29	539	0	0	568
Cash dividends declared	0	0	(5,407)	0	(5,407)
Balance at Sep. 30, 2012	7,843	57,045	88,478	8,679	162,045
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	12,604	0	12,604
Other comprehensive loss	0	0	0	(5,324)	(5,324)
Stock options exercised	17	292	0	0	309
Equity based compensation	22	402	0	0	424
Cash dividends declared	0	0	(5,433)	0	(5,433)
Balance at Sep. 30, 2013	$ 7,886	$ 57,905	$ 97,762	$ 2,273	$ 165,826