Condensed Consolidated Statements of Stockholders' Equity (USD $) In Thousands, except Share data, unless otherwise specified		Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Deferred Compensation [Member]	Treasury Stock [Member]
Beginning Balances at Dec. 31, 2012		$ 256,598	$ 4,671	$ 150,750	$ 106,239	$ (5,062)	$ 982	$ (982)
Beginning Balances, shares at Dec. 31, 2012	[1]		9,597,499
Common Stock, Dividends, Per Share, Declared		$ 1.52
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income		32,787			32,787
Other comprehensive loss/income		2,529				2,529
Dividends		(14,758)			(14,752)
Conversion of debentures		295	8	287
Conversion of debentures, shares	[1]		17,383
Share-based compensation	[2],[3]	1,322	12	1,310
Share-based compensation, shares	[1],[2],[3]		23,348
Stock Issued During Period, Shares, Dividend Reinvestment Plan			0
Stock Issued During Period, Value, Dividend Reinvestment Plan			0	(6)
Treasury Stock Activity During Period, Shares			0
Treasury Stock Activity And Deferred Compensation Plan Activity During Period Value		0	0	0			142	(142)
Ending Balances at Dec. 31, 2013		278,773	4,691	152,341	124,274	(2,533)	1,124	(1,124)
Ending Balances, shares at Dec. 31, 2013	[1]		9,638,230
Common Stock, Dividends, Per Share, Declared		$ 0.385
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income		17,681			17,681
Other comprehensive loss/income		31				31
Dividends		(3,780)			(3,779)
Conversion of debentures		535	15	520
Conversion of debentures, shares	[1]		31,542
Share-based compensation	[2],[3]	11	9	2
Share-based compensation, shares	[1],[2],[3]		17,906
Stock Issued During Period, Shares, Dividend Reinvestment Plan	[1]		0
Stock Issued During Period, Value, Dividend Reinvestment Plan			0	(1)
Treasury Stock Activity During Period, Shares			0
Treasury Stock Activity And Deferred Compensation Plan Activity During Period Value		0					14	(14)
Ending Balances at Mar. 31, 2014		$ 293,251	$ 4,715	$ 152,862	$ 138,176	$ (2,502)	$ 1,138	$ (1,138)
Ending Balances, shares at Mar. 31, 2014	[1]		9,687,678

[1] Includes 34,731 and 34,495 shares at March 31, 2014 and December 31, 2013, 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 SICP are net of shares withheld for employee taxes. For the quarter ended March 31, 2014 and for the year ended December 31, 2013, we withheld 8,458 and 10,411 shares, respectively, for taxes.