CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $) In Thousands, except Share data	Common Stock [Member]	Additional Paid-In Capital [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]	Total
Balance at Dec. 31, 2009	$ 309	$ 138,551	$ (135,712)	$ 3	$ 220,009	$ 223,160
Balance (shares) at Dec. 31, 2009	30,839,000
Purchase of treasury stock, at cost	0	0	(7,852)	0	0	(7,852)
Exercise of stock options	0	(1,963)	9,146	0	0	7,183
Income tax benefit from stock-based compensation, net	0	25	0	0	0	25
Stock-based compensation expense	0	(966)	9,092	0	0	8,126
Other	0	(40)	862	0	0	822
Dividends paid	0	0	0	0	(13,527)	(13,527)
Unrealized gain (loss) on marketable securities, net of tax	0	0	0	18	0	18
Net income	0	0	0	0	22,440	22,440
Balance at Dec. 31, 2010	309	135,607	(124,464)	21	228,922	240,395
Balance (shares) at Dec. 31, 2010	30,839,000
Purchase of treasury stock, at cost	0	0	(25,079)	0	0	(25,079)
Repurchase of treasury stock (in shares)						902,521
Exercise of stock options	0	(1,042)	4,998	0	0	3,956
Income tax benefit from stock-based compensation, net	0	1,663	0	0	0	1,663
Stock-based compensation expense	0	(416)	9,017	0	0	8,601
Other	0	59	881	0	0	940
Dividends paid	0	0	0	0	(15,742)	(15,742)
Unrealized gain (loss) on marketable securities, net of tax	0	0	0	3	0	3
Net income	0	0	0	0	30,470	30,470
Balance at Dec. 31, 2011	309	135,871	(134,647)	24	243,650	245,207
Balance (shares) at Dec. 31, 2011	30,839,000
Purchase of treasury stock, at cost	0	0	(13,773)	0	0	(13,773)
Repurchase of treasury stock (in shares)						407,400
Repurchase of common stock	(1)	(3,161)	0	0	0	(3,162)
Repurchase of common stock (in shares)	(81,000)
Exercise of stock options	0	(1,630)	3,879	0	0	2,249
Income tax benefit from stock-based compensation, net	0	1,751	0	0	0	1,751
Stock-based compensation expense	0	289	9,525	0	0	9,814
Other	0	87	1,066	0	0	1,153
Dividends paid	0	0	0	0	(42,728)	(42,728)
Unrealized gain (loss) on marketable securities, net of tax	0	0	0	(8)	0	(8)
Net income	0	0	0	0	40,402	40,402
Balance at Dec. 31, 2012	$ 308	$ 133,207	$ (133,950)	$ 16	$ 241,324	$ 240,905
Balance (shares) at Dec. 31, 2012	30,758,000