Condensed Consolidated Statements of Stockholders' Equity (Unaudited) (USD $) In Thousands, except Share data		Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Deferred Compensation	Treasury Stock
Balance at Dec. 31, 2009		$ 209,781	$ 4,572	$ 144,502	$ 63,231	$ (2,524)	$ 739	$ (739)
Balance, shares at Dec. 31, 2009	[1]		9,394,314
Net Income		26,056			26,056
Employee Benefit Plans, net of tax:
Amortization of prior service costs (4)	[2]	8				8
Net Gain (Loss) (5)	[3]	(844)				(844)
Total comprehensive income		25,220
Dividend Reinvestment Plan, shares	[1]		53,806
Dividend Reinvestment Plan		1,725	26	1,699
Retirement Savings Plan, shares	[1]		27,795
Retirement Savings Plan		903	14	889
Conversion of debentures, shares	[1]		11,865
Conversion of debentures		202	6	196
Tax benefit on share based compensation		253		253
Share based compensation (1)(3), shares	[1][4][5]		36,415
Share based compensation (1)(3)	[4][5]	637	17	620
Deferred Compensation Plan							38	(38)
Purchase of treasury stock, shares	[1]		(1,144)
Purchase of treasury stock		(38)						(38)
Sale and distribution of treasury stock, shares	[1]		1,144
Sale and distribution of treasury stock		38						38
Dividends on stock-based compensation		(104)			(104)
Cash dividends (2)	[6]	(12,378)			(12,378)
Balance at Dec. 31, 2010		226,239	4,635	148,159	76,805	(3,360)	777	(777)
Balance, shares at Dec. 31, 2010	[1]		9,524,195
Net Income		17,267			17,267
Employee Benefit Plans, net of tax:
Amortization of prior service costs (4)	[2]	4				4
Net Gain (Loss) (5)	[3]	357				357
Total comprehensive income		17,628
Dividend Reinvestment Plan		(11)		(11)
Retirement Savings Plan, shares	[1]		2,002
Retirement Savings Plan		80	1	79
Conversion of debentures, shares	[1]		5,691
Conversion of debentures		97	3	94
Share based compensation (1)(3), shares	[1][4][5]		30,430
Share based compensation (1)(3)	[4][5]	490	15	475
Deferred Compensation Plan							19	(19)
Purchase of treasury stock, shares	[1]		(473)
Purchase of treasury stock		(19)						(19)
Sale and distribution of treasury stock, shares	[1]		473
Sale and distribution of treasury stock		19						19
Dividends on stock-based compensation		(73)			(73)
Cash dividends (2)	[6]	(6,450)			(6,450)
Balance at Jun. 30, 2011		$ 238,000	$ 4,654	$ 148,796	$ 87,549	$ (2,999)	$ 796	$ (796)
Balance, shares at Jun. 30, 2011	[1]		9,562,318

[1] Includes 30,078 and 29,596 shares at June 30, 2011 and December 31, 2010, respectively, held in a Rabbi Trust established by the Company relating to the Deferred Compensation Plan.

[2] Tax expense recognized on the prior service cost component of employees benefit plans for the periods ended June 30, 2011 and December 31, 2010 were approximately $3 and $5, respectively.

[3] Tax expense (benefit) recognized on the net gain (loss) component of employees benefit plans for the periods ended June 30, 2011 and December 31, 2010, were $239 and ($541), respectively.

[4] Includes amounts for shares issued for Directors' compensation.

[5] The shares issued under the Performance Incentive Plan ("PIP") are net of shares withheld for employee taxes. For the periods ended June 30, 2011 and December 31, 2010 the Company withheld 12,324 and 17,695 shares, respectively, for taxes.

[6] Cash dividends declared per share for the periods ended June 30, 2011 and December 31, 2010 were $0.675 and $1.305, respectively.