Consolidated Balance Sheets Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Allowance for Doubtful Accounts Receivable, Current	$ 17,700	$ 18,100
Preferred Stock, Par or Stated Value Per Share	$ 1	$ 1
Preferred Stock, Shares Authorized	5,000,000	5,000,000
Preferred Stock, Shares Issued	0	0
Preferred Stock, Shares Outstanding	0	0
Common Stock, Par or Stated Value Per Share	$ 0.001	$ 0.001
Common Stock, Shares Authorized	125,000,000	125,000,000
Common Stock, Shares, Issued	56,153,140	54,313,107
Common Stock, Shares, Outstanding	53,960,158	54,313,107