Income Taxes (Details Textual) (USD $)	3 Months Ended		12 Months Ended
	Dec. 31, 2012	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Variable Interest Entity [Line Items]
Net operating loss carryforwards	$ 6,500,000		$ 6,500,000
Income Taxes (Textual) [Abstract]
Tax loss carryforwards	10,400,000		10,400,000		31,000,000
Pre-tax income from U.S. operations			82,000,000	74,300,000	46,100,000
U.S. federal tax at statutory rate			35.00%	35.00%	35.00%
Increase or decrease in net deferred tax assets			(643,000)	16,129,000	15,767,000
Stock compensation expense	5,296,000		5,296,000	5,312,000
Employee and non-employee awards	42,900,000		42,900,000
Percentage of change in ownership	50.00%		50.00%
Net operating loss carry forwards relating ownership change	25,600,000		25,600,000
Deemed net operating loss carry forward	10,600,000		10,600,000
Additional annual limitations			50% or greater change
Additional annual limitations period			3 years
Tax benefit		4,200,000		4,237,000	11,429,000
Reduction in income tax provision	6,700,000
Decrease in unrecognized tax benefit reserve	3,600,000
Increase unrecognized tax benefits	3,100,000		3,100,000
US Country [Member]
Variable Interest Entity [Line Items]
Net operating loss carryforwards	17,100,000		17,100,000
Net operating loss carryforwards, expiration date			begin to expire in 2021
Foreign Country [Member]
Variable Interest Entity [Line Items]
Pre-tax income from foreign operations			4,700,000	4,400,000	4,800,000
Net operating loss carryforwards	$ 700,000		$ 700,000
Net operating loss carryforwards, expiration date			begin to expire in 2025