Employee Benefit Plan (Details Textual) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Defined Contribution Plan Employer Discretionary Contribution Shares	107,728	93,472	48,440
Defined Contribution Plan Employer Discretionary Contribution Shares Value	$ 1,835,000	$ 1,108,000	$ 440,000
Defined Contribution Plan, Employer Discretionary Contribution Amount	150,000	334,000	160,000
Defined Contribution Plan, Cost Recognized	$ 2,086,000	$ 1,520,000	$ 601,000