Consolidated Statements Of Shareholders' Equity (USD $) In Thousands	Common Stock [Member]	Retained Earnings [Member]	Total
Balance at Dec. 31, 2008	$ 45,754	$ 204,127	$ 249,881
Balance, shares at Dec. 31, 2008	23,709
Net Income		33,325	33,325
Non-Cash Stock-Based Compensation	3,598		3,598
Non-Cash Stock-Based Compensation, shares
Common Stock Issued under Stock Plans, net of Shares Withheld for Employee Taxes	1,098		1,098
Common Stock Issued under Stock Plans, net of Shares Withheld for Employee Taxes, shares	86
Excess Tax Benefit from Equity Awards	419		419
Dividends Declared		(20,908)	(20,908)
Balance at Dec. 31, 2009	50,869	216,544	267,413
Balance, shares at Dec. 31, 2009	23,795
Net Income		36,479	36,479
Non-Cash Stock-Based Compensation	4,227		4,227
Non-Cash Stock-Based Compensation, shares
Common Stock Issued under Stock Plans, net of Shares Withheld for Employee Taxes	7,506		7,506
Common Stock Issued under Stock Plans, net of Shares Withheld for Employee Taxes, shares	440
Excess Tax Benefit from Equity Awards	1,021		1,021
Dividends Declared		(21,669)	(21,669)
Balance at Dec. 31, 2010	63,623	231,354	294,977
Balance, shares at Dec. 31, 2010	24,235		24,235
Net Income		49,602	49,602
Non-Cash Stock-Based Compensation	5,221		5,221
Non-Cash Stock-Based Compensation, shares
Common Stock Issued under Stock Plans, net of Shares Withheld for Employee Taxes	5,054		5,054
Common Stock Issued under Stock Plans, net of Shares Withheld for Employee Taxes, shares	341
Excess Tax Benefit from Equity Awards	980		980
Dividends Declared		(22,692)	(22,692)
Balance at Dec. 31, 2011	$ 74,878	$ 258,264	$ 333,142
Balance, shares at Dec. 31, 2011	24,576		24,576