Employee Benefit Plans - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule of Defined Benefit Plans And Defined Contribution Plans Disclosures [Table] [Line Items]
Compensation and benefits expense related to health plans	$ 15.1	$ 13.2	$ 12.1
Retirement Plan
Schedule of Defined Benefit Plans And Defined Contribution Plans Disclosures [Table] [Line Items]
Maximum 401(k) plan contribution rates as percentage of employee earnings	100.00%
Retirement plan, employer matching contribution as a percentage of employees' gross pay	6.00%
Health and Welfare Plans
Schedule of Defined Benefit Plans And Defined Contribution Plans Disclosures [Table] [Line Items]
Compensation and benefits expense related to health plans	$ 9.1	$ 7.7	$ 7.2