Consolidated Statements of Changes in Shareholders' Equity (Unaudited) (USD $) In Thousands	Capital Stock	Surplus	Undivided Profits	Accumulated Other Comprehensive Income [Member]	Comprehensive Income [Member]	Treasury Stock [Member]	Total
Balance at Dec. 31, 2009	$ 83,166	$ 128,681	$ 99,190	$ (1,282)		$ (64,077)	$ 245,678
Comprehensive income:
Net Income	0	0	14,059	0	14,059	0	14,059
Other comprehensive income, net of tax:
Amortization of prior service cost on pension and post retirement plans, net of tax	0	0	0	0	(122)	0	0
Unrealized net holding gain on securities available-for-sale arising during the period, net of tax	0	0	0	0	4,617	0	0
Reclassification adjustment for net gain realized in net income during the period	0	0	0	0	(929)	0	0
Other comprehensive income, net of tax:				3,566	3,566		3,566
Comprehensive income	0	0	0		17,625	0	0
Cash dividend declared	0	0	(9,602)	0		0	(9,602)
Sale of treasury stock	0	(783)	0	0		2,182	1,399
Stock based compensation expense	0	89	0	0		0	89
Balance at Jun. 30, 2010	83,166	127,987	103,647	2,284		(61,895)	255,189
Balance at Mar. 31, 2010	83,166	128,344	101,327	777		(62,996)	250,618
Comprehensive income:
Net Income	0	0	7,124	0	7,124	0	7,124
Other comprehensive income, net of tax:
Amortization of prior service cost on pension and post retirement plans, net of tax	0	0	0	0	(61)	0	0
Unrealized net holding gain on securities available-for-sale arising during the period, net of tax	0	0	0	0	2,495	0	0
Reclassification adjustment for net gain realized in net income during the period	0	0	0	0	(927)	0	0
Other comprehensive income, net of tax:				1,507	1,507		1,507
Comprehensive income	0	0	0		8,631	0	0
Cash dividend declared	0	0	(4,804)	0		0	(4,804)
Sale of treasury stock	0	(402)	0	0		1,101	699
Stock based compensation expense	0	45	0	0		0	45
Balance at Jun. 30, 2010	83,166	127,987	103,647	2,284		(61,895)	255,189
Balance at Dec. 31, 2010	83,166	126,982	108,780	(4,119)		(59,369)	255,440
Comprehensive income:
Net Income	0	0	15,148	0	15,148	0	15,148
Other comprehensive income, net of tax:
Amortization of prior service cost on pension and post retirement plans, net of tax	0	0	0	0	(54)	0	0
Unrealized net holding gain on securities available-for-sale arising during the period, net of tax	0	0	0	0	7,704	0	0
Reclassification adjustment for net gain realized in net income during the period	0	0	0	0	(685)	0	0
Other comprehensive income, net of tax:				6,965	6,965		6,965
Comprehensive income	0	0	0		22,113	0	0
Cash dividend declared	0	0	(10,146)	0		0	(10,146)
Sale of treasury stock	0	(860)	0	0		2,328	1,468
Stock based compensation expense	0	74	0	0		0	74
Balance at Jun. 30, 2011	83,166	126,196	113,782	2,846		(57,041)	268,949
Balance at Mar. 31, 2011	83,166	126,638	111,093	(4,176)		(58,249)	258,472
Comprehensive income:
Net Income	0	0	7,766	0	7,766	0	7,766
Other comprehensive income, net of tax:
Amortization of prior service cost on pension and post retirement plans, net of tax	0	0	0	0	(5)	0	0
Unrealized net holding gain on securities available-for-sale arising during the period, net of tax	0	0	0	0	7,539	0	0
Reclassification adjustment for net gain realized in net income during the period	0	0	0	0	(512)	0	0
Other comprehensive income, net of tax:				7,022	7,022		7,022
Comprehensive income	0	0	0		14,788	0	0
Cash dividend declared	0	0	(5,077)	0		0	(5,077)
Sale of treasury stock	0	(479)	0	0		1,208	729
Stock based compensation expense	0	37	0	0		0	37
Balance at Jun. 30, 2011	$ 83,166	$ 126,196	$ 113,782	$ 2,846		$ (57,041)	$ 268,949