Stock Incentive Plans (Details Textual) (USD $)	0 Months Ended	1 Months Ended									2 Months Ended					12 Months Ended							1 Months Ended			0 Months Ended
	Aug. 02, 2011	Jul. 31, 2012	Jan. 31, 2012	Dec. 31, 2011	Oct. 31, 2011	Jul. 31, 2011	May 31, 2011	Jan. 31, 2011	Oct. 31, 2010	Feb. 28, 2010	Oct. 31, 2012	May 31, 2012	Apr. 30, 2011	Aug. 31, 2010	Apr. 30, 2010	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Restricted stock [Member]	Dec. 31, 2011 Restricted stock [Member]	Dec. 31, 2010 Restricted stock [Member]	Dec. 31, 2009 Board of Directors [Member]	Jun. 30, 2011 2007 Plan [Member]	Jun. 22, 2011 2007 Plan [Member] Maximum [Member]	Jun. 22, 2011 2007 Plan [Member] Minimum [Member]	Aug. 02, 2011 2001 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares awarded or sold																								4,407,692	2,307,692	1,449,667
Plan expiration date																										Aug. 02, 2011
Increase in maximum number of shares awarded or sold under 2007 plan																							2,100,000
Stock options to purchase shares of common stock granted		7,000	8,500	143,000	75,400	12,500	51,650	26,000	35,000	7,500	36,800	36,750	73,500	145,655	50,671	89,050	382,050	238,826				300,000
Exercise price																$ 9.72	$ 16.02	$ 27.54				$ 19.21
Stock compensation expense																$ 1,800,000	$ 2,300,000	$ 2,100,000	$ 162,000	$ 165,000	$ 153,000
Stock Incentive Plans (Textual) [Abstract]
Number of share of common stock purchased	1
Weighted average fair value of the options vested																8,000,000	3,900,000	2,900,000
Intrinsic value of the options outstanding and exercisable				0												0	0	14,800,000
Intrinsic value for options exercisable				0												0	0	5,500,000
Unrecognized compensation cost related to non vested awards																$ 3,100,000
Stock based plan expect to recognize weighted average period																2 years 1 month 21 days
Weighted average fair value per share of options granted																$ 9.72	$ 16.02	$ 27.54
Expected term																5 years 3 months 18 days	5 years	5 years 4 months 24 days
Risk free interest rate, Minimum																0.62%	0.85%	1.26%
Risk free interest rate, Maximum																1.04%	2.24%	2.60%
Expected volatility																52.00%	51.00%	60.00%
Dividend yield																0.00%	0.00%	0.00%
Expected forfeiture rate																16.59%	24.53%	27.54%