CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY AND COMPREHENSIVE INCOME (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Treasury Stock
Balance at Dec. 31, 2009	$ 326,398	$ 362	$ 248,937	$ (1,815)	$ 79,772	$ (858)
Balance (in shares) at Dec. 31, 2009		36,238,000				(56,000)
Increase (Decrease) in Stockholders' Equity
Net income	13,929				13,929
Foreign currency translation adjustment	(156)			(156)
Tax benefit/deficiency from share-based compensation	(211)		(211)
Restricted common stock issued under share-based compensation plans	1,460	5	(1,478)			2,933
Restricted common stock issued under share-based compensation plans (in shares)		497,000				219,000
Common stock repurchased under share-based compensation plans	(948)					(948)
Common stock repurchased under share-based compensation plans (in shares)	(76,087)					(76,000)
Share repurchases (Note 7)	(43,212)					(43,212)
Share repurchases (Note 7) (in shares)						(3,382,000)
Conversion of convertible notes (Note 5)	27,168	24	27,144
Conversion of convertible notes (Note 5) (in shares)		2,328,000
Dividends declared ($0.385, $0.205 and $0.07 per share for the years ended December 31, 2012, 2011 and 2010, respectively) (Note 7)	(2,632)				(2,632)
Share-based compensation expense	6,727		6,727
Balance at Dec. 31, 2010	328,523	391	281,119	(1,971)	91,069	(42,085)
Balance (in shares) at Dec. 31, 2010		39,063,000				(3,295,000)
Increase (Decrease) in Stockholders' Equity
Net income	12,080				12,080
Foreign currency translation adjustment	(16)			(16)
Tax benefit/deficiency from share-based compensation	264		264
Restricted common stock issued under share-based compensation plans	2,857	4	(1,883)			4,736
Restricted common stock issued under share-based compensation plans (in shares)		431,000				367,000
Common stock repurchased under share-based compensation plans	(900)					(900)
Common stock repurchased under share-based compensation plans (in shares)	(66,290)					(67,000)
Share repurchases (Note 7)	(9,958)					(9,958)
Share repurchases (Note 7) (in shares)						(745,000)
Dividends declared ($0.385, $0.205 and $0.07 per share for the years ended December 31, 2012, 2011 and 2010, respectively) (Note 7)	(7,300)				(7,300)
Share-based compensation expense	7,369		7,369
Balance at Dec. 31, 2011	332,919	395	286,869	(1,987)	95,849	(48,207)
Balance (in shares) at Dec. 31, 2011		39,494,000				(3,740,000)
Increase (Decrease) in Stockholders' Equity
Net income	22,427				22,427
Foreign currency translation adjustment	555			555
Tax benefit/deficiency from share-based compensation	(315)		(315)
Restricted common stock issued under share-based compensation plans	4	4
Restricted common stock issued under share-based compensation plans (in shares)		430,000
Stock option exercises	880		(2,208)			3,088
Stock option exercises (in shares)						240,000
Common stock repurchased under share-based compensation plans	(2,689)					(2,689)
Common stock repurchased under share-based compensation plans (in shares)	(217,713)					(217,000)
Share repurchases (Note 7)	(3,299)					(3,299)
Share repurchases (Note 7) (in shares)						(284,000)
Dividends declared ($0.385, $0.205 and $0.07 per share for the years ended December 31, 2012, 2011 and 2010, respectively) (Note 7)	(13,831)				(13,831)
Share-based compensation expense	6,719		6,719
Balance at Dec. 31, 2012	$ 343,370	$ 399	$ 291,065	$ (1,432)	$ 104,445	$ (51,107)
Balance (in shares) at Dec. 31, 2012		39,924,000				(4,001,000)