Income Taxes (Details 5) (USD $)	12 Months Ended
	Dec. 31, 2011
Income Taxes
Uncertain income tax positions not recognized, if percentage is less than, likelihood of being sustained (as a percent)	50.00%
Summary the gross amounts of unrecognized tax benefits
Unrecognized tax benefits, balance at the beginning of the period	$ 8,968,000
Decrease for prior period tax positions	(97,000)
Increase for current period tax positions	963,000
Unrecognized tax benefits, balance at the end of the period	9,834,000
Net effect on the deferred tax assets resulting from unrecognized tax benefits	$ 742,000