Employee Benefit Plans - Additional Information (Details) - USD ($)	9 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Current deferred compensation liability	$ 3,700,000	$ 2,300,000
Deferred compensation plan	25,800,000	24,200,000
Deferred Compensation Plan Assets	27,000,000	25,500,000
Supplemental Executive Retirement Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Supplemental executive retirement plan	12,700,000	$ 11,300,000
Employer contributions to benefit plans	$ 0