Stock Incentive Plans (Details Textual) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Stock Incentive Plans [Line Items]
Number of common stock authorized for Long-Term Incentive Plan	6,200,000		6,200,000
Stock-based compensation expense	$ 3,956,000	$ 2,592,000	$ 16,650,000	$ 16,229,000
Option expiration period	10 years
Director [Member]
Stock Incentive Plans [Line Items]
Vesting period	3 years
Officer [Member]
Stock Incentive Plans [Line Items]
Vesting period	5 years