Consolidated Statements of Stockholders' Equity (USD $)		Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Deferred Compensation	Treasury Stock
Beginning Balances at Dec. 31, 2010		$ 226,239,000	$ 4,635,000	$ 148,159,000	$ 76,805,000	$ (3,360,000)	$ 777,000	$ (777,000)
Beginning Balances, shares at Dec. 31, 2010	[1]		9,524,195.000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income		27,622,000			27,622,000
Other comprehensive loss		(1,167,000)				(1,167,000)
Dividends ShareBased Compensation Dividends And Dividends For Reinvestment Plan		13,201,000	0	22,000	13,179,000	0	0	0
Dividend Reinvestment Plan, shares	[1]		0
Retirement Savings Plan		80,000	1,000	79,000
Retirement Savings Plan, shares	[1]		2,002.000
Conversion of Debentures		181,000	5,000	176,000
Conversion of debentures, shares	[1]		10,680.00
Share-based compensation	[2],[3]	1,026,000	15,000	1,011,000	0	0	0	0
Share-based compensation, shares	[1],[2],[3]		30,430.00
Tax benefit on share-based compensation				13,000
Purchase of treasury stock, shares	[1]		0
Treasury stock activities	[1]	0	0	0	0	0	(40,000)	40,000
Deferred compensation plan held Rabbi Trust		30,597
Share issued under the performance incentive plan withheld for employee taxes		12,234
Cash Dividends Declared Per Share of Common Stock (in usd per share)		$ 1.365
Ending Balances at Dec. 31, 2011		240,780,000	4,656,000	149,403,000	91,248,000	(4,527,000)	817,000	(817,000)
Ending Balances, shares at Dec. 31, 2011	[1]		9,567,307.000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income		28,863,000			28,863,000
Other comprehensive loss		(535,000)				(535,000)
Dividends ShareBased Compensation Dividends And Dividends For Reinvestment Plan		13,879,000	0	7,000	13,872,000	0	0	0
Dividend Reinvestment Plan, shares	[1]		0
Conversion of Debentures		186,000	5,000	181,000
Conversion of debentures, shares	[1]		10,975
Share-based compensation	[2],[3]	1,183,000	10,000	1,173,000	0	0	0	0
Share-based compensation, shares	[1],[2],[3]		19,217
Tax benefit on share-based compensation				172,000
Purchase of treasury stock, shares	[1]		0
Treasury stock activities	[1]	0	0	0	0	0	(165,000)	165,000
Deferred compensation plan held Rabbi Trust		33,461
Share issued under the performance incentive plan withheld for employee taxes		5,670
Cash Dividends Declared Per Share of Common Stock (in usd per share)		$ 1.44
Ending Balances at Dec. 31, 2012		256,598,000	4,671,000	150,750,000	106,239,000	(5,062,000)	982,000	(982,000)
Ending Balances, shares at Dec. 31, 2012	[1]		9,597,499
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income		32,787,000			32,787,000
Other comprehensive loss		2,529,000				2,529,000
Dividends ShareBased Compensation Dividends And Dividends For Reinvestment Plan		14,758,000	0	6,000	14,752,000	0	0	0
Dividend Reinvestment Plan, shares	[1]		0
Conversion of Debentures		295,000	8,000	287,000
Conversion of debentures, shares	[1]		17,383
Share-based compensation	[2],[3]	1,322,000	12,000	1,310,000	0	0	0	0
Share-based compensation, shares	[1],[2],[3]		23,348
Tax benefit on share-based compensation				202,000
Purchase of treasury stock, shares	[1]		0
Treasury stock activities	[1]	0	0	0	0	0	(142,000)	142,000
Deferred compensation plan held Rabbi Trust		34,495
Share issued under the performance incentive plan withheld for employee taxes		10,411
Cash Dividends Declared Per Share of Common Stock (in usd per share)		$ 1.52
Ending Balances at Dec. 31, 2013		$ 278,773,000	$ 4,691,000	$ 152,341,000	$ 124,274,000	$ (2,533,000)	$ 1,124,000	$ (1,124,000)
Ending Balances, shares at Dec. 31, 2013	[1]		9,638,230

[1] Includes 34,495, 33,461 and 30,597 shares at December 31, 2013, 2012 and 2011, respectively, held in a Rabbi Trust related to our Deferred Compensation Plan.

[2] Includes amounts for shares issued for Directors’ compensation.

[3] The shares issued under the PIP are net of shares withheld for employee taxes. For 2013, 2012 and 2011, we withheld 10,411, 5,670 and 12,234 shares, respectively, for taxes.