Income Taxes (Details Textual) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2011	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2012	Dec. 31, 2008
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards		$ 8,300,000
Income Taxes (Textual) [Abstract]
Pre-tax income from U.S operations		74,300,000	46,100,000	21,600,000
U.S. federal statutory rate		35.00%	35.00%	35.00%
Increase or decrease in net deferred tax assets		16,129,000	15,767,000	12,255,000
Stock compensation expense		5,312,000	6,945,000
Employee and non-employee awards		27,900,000
Net operating loss carryforwards relating ownership change		23,200,000
Deemed net operating loss carryforward		4,000,000
Additional annual limitations		50% or greater change
Additional annual limitations, period		3 years
Percentage of change in ownership		50.00%
Tax Benefit	4,200,000	4,237,000	11,429,000
Tax loss carryforward	10,400,000		31,000,000
Unrecognized tax benefits		3,647,000	3,329,000	2,924,000		2,685,000
Increase unrecognized tax benefits					400,000
US Country [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards		12,300,000
Net operating loss carryforwards, expiration date		begin to expire in 2021
Foreign Country [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards		700,000
Net operating loss carryforwards, expiration date		begin to expire in 2025
Pre-tax income from foreign operations		$ 4,400,000	$ 4,800,000	$ 8,400,000