Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Allowance for doubtful accounts	$ 1,183	$ 1,066
Preferred stock, par value (per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	500,000	500,000
Preferred stock, shares issued
Preferred stock, shares outstanding
Common stock, par value (per share)	$ 0.01	$ 0.01
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	31,299,203	31,299,203
Treasury stock, shares	3,358,078	3,077,377