Summary of Significant Accounting Policies (Details) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011
Summary of Significant Accounting Policies [Abstract]
Estimated Effective Income Tax Rate			39.00%
Effective Income Tax Rate, Continuing Operations	23.00%
Current Foreign Tax Expense (Benefit)	$ 11,864,000	$ 7,425,000
U.S. federal statutory rate	35.00%
Excess tax benefits from stock-based compensation	7,611,000	23,000
Cash Paid for Income Taxes	0
Operating loss carryforwards, federal				69,062,000
Operating loss carryforwards, state				61,493,000
Available for sale securities, amortized cost, common stock investments	8,427,000
Unrealized gain (loss) on investment, common stock	1,051,000
Available for sale securities, amortized cost, government securities	124,762,000
Unrealized gain (loss) on investment, government securities	55,000
Business acquisition deferred tax asset	1,900,000
Income tax benefit	10,237,000	0
Change in deferred tax liability, business acquisition	$ 8,300,000