Balance Sheet Parenthetical (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Allowance for Doubtful Accounts Receivable, Current	$ 3,762	$ 3,396
Common Stock, Par or Stated Value Per Share	$ 0.02	$ 0.02
Common Stock, Shares Authorized	200,000,000	200,000,000
Common Stock, Shares, Issued	49,037,806	49,739,912
Common Stock, Shares, Outstanding	47,629,472	45,521,186
Treasury Stock, Shares	1,408,334	4,218,726
Preferred Stock, Par or Stated Value Per Share	$ 0.02	$ 0.02
Preferred Stock, Shares Authorized	6,000,000	6,000,000
Preferred Stock, Shares Issued	0	0
Preferred Stock, Shares Outstanding	0	0