Consolidated Statement Of Stockholders' Equity (USD $) In Thousands	Common Stock [Member]	Paid-In Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Total
Balance - at Dec. 31, 2009	$ 246	$ 74,239	$ 197,430	$ (27,800)	$ 244,115
Net income			28,034		28,034
Issuance of shares of common stock pursuant to stock options, deferred stock units and restricted stock	1	1,134			1,135
Income tax benefit relating to issuance of common stock pursuant to stock options, deferred stock units and restricted stock		11			11
Stock-based compensation expense		4,176			4,176
Issuance of deferred stock units relating to prior year compensation		61			61
Special cash dividend			(33,032)		(33,032)
Dividend equivalents on deferred stock units and restricted stock		365	(365)
Purchase of shares of treasury stock				(1,041)	(1,041)
Balance - at Dec. 31, 2010	247	79,986	192,067	(28,841)	243,459
Net income			30,059		30,059
Issuance of shares of common stock pursuant to stock options, deferred stock units and restricted stock	1	996			997
Income tax benefit relating to issuance of common stock pursuant to stock options, deferred stock units and restricted stock		216			216
Reversal of deferred tax assets due to expiration of vested stock options		(2,496)			(2,496)
Stock-based compensation expense		4,587			4,587
Issuance of deferred stock units relating to prior year compensation		1,100			1,100
Purchase of shares of treasury stock				(626)	(626)
Balance - at Dec. 31, 2011	248	84,389	222,126	(29,467)	277,296
Net income			37,340		37,340
Issuance of shares of common stock pursuant to stock options, deferred stock units and restricted stock	6	7,853			7,859
Income tax benefit relating to issuance of common stock pursuant to stock options, deferred stock units and restricted stock		270			270
Stock-based compensation expense		6,318			6,318
Issuance of deferred stock units relating to prior year compensation		200			200
Special cash dividend			(45,038)		(45,038)
Dividend equivalents on deferred stock units and restricted stock		1,382	(1,382)
Balance - at Dec. 31, 2012	$ 254	$ 100,412	$ 213,046	$ (29,467)	$ 284,245