Consolidated Statements Of Stockholders' Equity And Comprehensive Income (USD $) In Thousands	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total
Balance at Dec. 31, 2009	$ 118,243	$ 333,612	$ 1,217,975	$ (1,236,217)	$ (31,970)	$ 401,643
Exercise of stock options and release of nonvested shares	53	22	0	(124)	0	(49)
Net tax effect of options exercised and release of nonvested shares	0	(588)	0	0	0	(588)
Stock-based compensation	0	3,907	0	0	0	3,907
Dividends paid	0	0	(19,141)	0	0	(19,141)
Treasury stock issued	0	(158)	0	317	0	159
Comprehensive Income
Net income	0	0	53,604	0	0	53,604
Adjustment to pension liability	0	0	0	0	(1,576)	(1,576)
Foreign currency translation adjustment	0	0	0	0	(136)	(136)
Total comprehensive income						51,892
Balance at Dec. 31, 2010	118,296	336,795	1,252,438	(1,236,024)	(33,682)	437,823
Exercise of stock options and release of nonvested shares	155	531	0	(98)	0	588
Net tax effect of options exercised and release of nonvested shares	0	(732)	0	0	0	(732)
Stock-based compensation	0	2,812	0	0	0	2,812
Dividends paid	0	0	(10,253)	0	0	(10,253)
Treasury stock issued	0	(67)	0	149	0	82
Purchase of treasury stock	0	0	0	(8,363)	0	(8,363)
Comprehensive Income
Net income	0	0	17,342	0	0	17,342
Adjustment to pension liability	0	0	0	0	1,370	1,370
Foreign currency translation adjustment	0	0	0	0	1,024	1,024
Total comprehensive income						19,736
Balance at Jun. 30, 2011	$ 118,451	$ 339,339	$ 1,259,527	$ (1,244,336)	$ (31,288)	$ 441,693