Employee Benefit Plans (Details Textual) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Employee Benefit Plan Obligations (Textual) [Abstract]
Company's expense for its defined contribution plans	$ 10,300,000	$ 8,800,000	$ 7,800,000
Contributions to the defined benefit pension plan	$ 1,500,000
Supplemental Employee Retirement Plan
Employee Benefit Plan Obligations (Textual) [Abstract]
Calculated rate for the supplemental employee retirement plan	2.90%	2.10%	3.20%
Discount rate	2.10%	3.20%	4.20%