Condensed 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, 2011	$ 248	$ 84,389	$ 222,126	$ (29,467)	$ 277,296
Net income			32,595		32,595
Issuance of 243,848 shares of common stock pursuant to stock options and deferred stock units	2	2,732			2,734
Income tax benefit relating to issuance of common stock pursuant to stock options and deferred stock units		106			106
Stock-based compensation expense		4,703			4,703
Issuance of 7,548 deferred stock units relating to prior year compensation		200			200
Balance - at Sep. 30, 2012	$ 250	$ 92,130	$ 254,721	$ (29,467)	$ 317,634