Stock Incentive Plans (Details Textual) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
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	$ 5,477,000	$ 4,271,000	$ 25,655,000	$ 26,108,000
Maximum [Member]
Stock Incentive Plans [Line Items]
Vesting period			5 years
Minimum [Member]
Stock Incentive Plans [Line Items]
Vesting period			3 years
Employee Stock Option [Member] | Employee Stock Option [Member]
Stock Incentive Plans [Line Items]
Vesting period			10 years
Employee Stock Option [Member] | Employee Stock Option [Member] | Director [Member]
Stock Incentive Plans [Line Items]
Vesting period			3 years
Employee Stock Option [Member] | Employee Stock Option [Member] | Officer [Member]
Stock Incentive Plans [Line Items]
Vesting period			5 years