CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (USD $) In Thousands	Total	Common Stock	Additional Capital	Retained Earnings	Accumulated Other Comprehensive Income/(Loss)	Treasury Stock	Comprehensive Income
Balance at Mar. 31, 2010	$ 316,096	$ 1,806	$ 68,739	$ 283,043	$ (3,526)	$ (33,966)
Comprehensive income:
Net income	7,713			7,713			7,713
Change in net unrealized gains/(losses) on securities available for-sale	1,324				1,324		1,324
Change in funded status of retirement plans	178				178		178
Total comprehensive income/(loss)	9,215						9,215
Cash Dividends, $.47 and $.46 per share for the three months ended 2011 and 2010 and $.47 and $.46 per share for the six months ended 2011 and 2010, respectively	(6,032)			(6,032)
Treasury stock purchase (3,500 shares for three months ended 2011 and 2010 and 20,500 shares for six months ended 2011 and 2010)	(93)					(93)
Balance at Jun. 30, 2010	319,186	1,806	68,739	284,724	(2,024)	(34,059)
Balance at Dec. 31, 2009	306,483	1,806	68,739	277,357	(7,904)	(33,515)
Comprehensive income:
Net income	13,399			13,399			13,399
Change in net unrealized gains/(losses) on securities available for-sale	5,524				5,524		5,524
Change in funded status of retirement plans	356				356		356
Total comprehensive income/(loss)	19,279						19,279
Cash Dividends, $.47 and $.46 per share for the three months ended 2011 and 2010 and $.47 and $.46 per share for the six months ended 2011 and 2010, respectively	(6,032)			(6,032)
Treasury stock purchase (3,500 shares for three months ended 2011 and 2010 and 20,500 shares for six months ended 2011 and 2010)	(544)					(544)
Balance at Jun. 30, 2010	319,186	1,806	68,739	284,724	(2,024)	(34,059)
Balance at Dec. 31, 2010	321,717	1,806	68,944	293,319	(9,369)	(32,983)
Comprehensive income:
Net income	17,220			17,220			17,220
Change in net unrealized gains/(losses) on securities available for-sale	9,304				9,304		9,304
Change in funded status of retirement plans	605				605		605
Total comprehensive income/(loss)	27,129						27,129
Cash Dividends, $.47 and $.46 per share for the three months ended 2011 and 2010 and $.47 and $.46 per share for the six months ended 2011 and 2010, respectively	(6,181)			(6,181)
Balance at Jun. 30, 2011	342,665	1,806	68,944	304,358	540	(32,983)
Balance at Mar. 31, 2011	334,632	1,806	68,944	302,122	(5,257)	(32,983)
Comprehensive income:
Net income	8,417			8,417			8,417
Change in net unrealized gains/(losses) on securities available for-sale	5,495				5,495		5,495
Change in funded status of retirement plans	302				302		302
Total comprehensive income/(loss)	14,214						14,214
Cash Dividends, $.47 and $.46 per share for the three months ended 2011 and 2010 and $.47 and $.46 per share for the six months ended 2011 and 2010, respectively	(6,181)			(6,181)
Balance at Jun. 30, 2011	$ 342,665	$ 1,806	$ 68,944	$ 304,358	$ 540	$ (32,983)