CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (USD $)	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Treasury Stock
Balance at Dec. 31, 2010	$ 328,523,000	$ 391,000	$ 281,119,000	$ (1,971,000)	$ 91,069,000	$ (42,085,000)
Balance (in shares) at Dec. 31, 2010		39,063,000				(3,295,000)
Increase (Decrease) in Stockholders' Equity
Net income	12,080,000				12,080,000
Foreign currency translation adjustment	(16,000)			(16,000)
Tax benefit/deficiency from share-based compensation	264,000		264,000
Restricted common stock issued under share-based compensation plans	2,857,000	4,000	(1,883,000)			4,736,000
Restricted common stock issued under share-based compensation plans (in shares)		431,000				367,000
Common stock repurchased under share-based compensation plans	(900,000)					(900,000)
Common stock repurchased under share-based compensation plans (in shares)	(66,290)					(67,000)
Share repurchases (Note 7)	(9,958,000)					(9,958,000)
Share repurchases (Note 7) (in shares)						(745,000)
Dividends declared ($0.36, $0.385 and $0.205 per share for the year ended December 31, 2013, 2012 and 2011 respectively) (Note 7)	(7,300,000)				(7,300,000)
Share-based compensation expense	7,369,000		7,369,000
Balance at Dec. 31, 2011	332,919,000	395,000	286,869,000	(1,987,000)	95,849,000	(48,207,000)
Balance (in shares) at Dec. 31, 2011		39,494,000				(3,740,000)
Increase (Decrease) in Stockholders' Equity
Net income	22,427,000				22,427,000
Foreign currency translation adjustment	555,000			555,000
Tax benefit/deficiency from share-based compensation	(315,000)		(315,000)
Restricted common stock issued under share-based compensation plans	4,000	4,000
Restricted common stock issued under share-based compensation plans (in shares)		430,000
Stock option exercises	880,000		(2,208,000)			3,088,000
Stock option exercises (in shares)						240,000
Common stock repurchased under share-based compensation plans	(2,689,000)					(2,689,000)
Common stock repurchased under share-based compensation plans (in shares)	(217,713)					(217,000)
Share repurchases (Note 7)	(3,299,000)					(3,299,000)
Share repurchases (Note 7) (in shares)						(284,000)
Dividends declared ($0.36, $0.385 and $0.205 per share for the year ended December 31, 2013, 2012 and 2011 respectively) (Note 7)	(13,831,000)				(13,831,000)
Share-based compensation expense	6,719,000		6,719,000
Balance at Dec. 31, 2012	343,370,000	399,000	291,065,000	(1,432,000)	104,445,000	(51,107,000)
Balance (in shares) at Dec. 31, 2012		39,924,000				(4,001,000)
Increase (Decrease) in Stockholders' Equity
Net income	11,110,000				11,110,000
Foreign currency translation adjustment	891,000			891,000
Tax benefit/deficiency from share-based compensation	2,828,000		2,828,000
Restricted common stock issued under share-based compensation plans	4,000	4,000	(2,020,000)			2,020,000
Restricted common stock issued under share-based compensation plans (in shares)		375,000				153,000
Stock option exercises	3,001,000		(7,466,000)			10,467,000
Stock option exercises (in shares)						780,000
Common stock repurchased under share-based compensation plans	(6,515,000)					(6,515,000)
Common stock repurchased under share-based compensation plans (in shares)	(471,248)					(471,000)
Share repurchases (Note 7)	(22,881,000)					(22,881,000)
Share repurchases (Note 7) (in shares)						(1,768,000)
Dividends declared ($0.36, $0.385 and $0.205 per share for the year ended December 31, 2013, 2012 and 2011 respectively) (Note 7)	(12,801,000)				(12,801,000)
Share-based compensation expense	7,007,000		7,007,000
Balance at Dec. 31, 2013	$ 326,014,000	$ 403,000	$ 291,414,000	$ (541,000)	$ 102,754,000	$ (68,016,000)
Balance (in shares) at Dec. 31, 2013		40,299,000				(5,307,000)