CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Accounts receivable, allowance for doubtful accounts (in dollars)	$ 2,919	$ 2,086
Preferred Stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred Stock, shares authorized	100	100
Preferred Stock, shares issued	0	0
Preferred Stock, shares outstanding	0	0
Common Stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common Stock, shares authorized	240,000	240,000
Common Stock, shares issued	90,295	90,277
Common Stock, shares outstanding	90,295	90,277
Non-voting Common Stock
Common Stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common Stock, shares authorized	7,125	7,125
Common Stock, shares issued	0	0
Common Stock, shares outstanding	0	0
Class C Common Stock
Common Stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common Stock, shares authorized	20,000	20,000
Common Stock, shares issued	0	0
Common Stock, shares outstanding	0	0