CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited) (USD $) In Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]
Balance at Dec. 31, 2011	$ 245,207	$ 309	$ 135,871	$ (134,647)	$ 24	$ 243,650
Balance (in shares) at Dec. 31, 2011		30,839
Purchase of treasury stock, at cost	(11,741)	0	0	(11,741)	0	0
Exercise of stock options	1,044	0	(470)	1,514	0	0
Income tax benefit from stock-based compensation, net	1,193	0	1,193	0	0	0
Stock-based compensation expense	4,956	0	100	4,856	0	0
Other	619	0	68	551	0	0
Dividends paid	(8,285)	0	0	0	0	(8,285)
Unrealized gain on marketable securities, net of tax	34	0	0	0	34	0
Net income	19,505	0	0	0	0	19,505
Balance at Jun. 30, 2012	$ 252,532	$ 309	$ 136,762	$ (139,467)	$ 58	$ 254,870
Balance (in shares) at Jun. 30, 2012		30,839