Treasury Stock (Details) (USD $)	9 Months Ended		1 Months Ended	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Aug. 31, 2012 Common Stock Class A	Sep. 30, 2012 Common Stock Class A
Equity, Class of Treasury Stock [Line Items]
Common stock repurchase program, maximum authorized amount			$ 15,000,000	$ 35,000,000
Treasury Stock [Roll Forward]
Treasury stock, shares, beginning of period				5,346,003
Treasury stock, cost, beginning of period				16,902,000
Treasury stock, average cost per share, beginning of period, in dollars per share				$ 3.16
Shares purchased for minimum tax withholding, shares				1,062,296
Shares purchased for minimum tax withholding, cost	2,652,000	1,566,000		2,652,000
Shares purchased for minimum tax withholding, average cost per share, in dollars per share				$ 2.50
Purchase of treasury stock, shares				3,211,852
Purchase of treasury stock, cost				8,252,000
Treasury stock acquired, average cost per share, in dollars per share				$ 2.57
Treasury stock, shares, end of period				9,620,151
Treasury stock, cost, end of period				$ 27,806,000
Treasury stock, average cost per share, end of period, in dollars per share				$ 2.89