Employee Benefits - Narrative (Details) - USD ($) $ in Millions		12 Months Ended
	Sep. 30, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Definedcontributionemployeeautomaticcontributionpercentag		6.00%
Company 401K plan contribution (percentage)	1.50%	3.00%
Employee salary deferral contributions percentage vested		100.00%
Employer contribution annual vesting percentage		20.00%
Employer matching contribution, percent of match		100.00%
Maximum annual contributions per employee, percent		6.00%
Employer contribution vesting period		years two through six of employment
Employer matching contributions		$ 9.0	$ 6.8	$ 3.0
Administrative expenses		$ 0.1	0.2	0.2
Profits sharing, percent of pre-tax profit paid to eligible employees on quarterly basis		10.00%
Profit sharing expense		$ 8.0	$ 7.8	$ 6.4
Effective January 1, 2016 [Member]
Defined Benefit Plan Disclosure [Line Items]
Company 401K plan contribution (percentage)		3.00%
Employer matching contribution, percent of match		175.00%
Maximum annual contributions per employee, percent		6.00%
Over Two Years
Defined Benefit Plan Disclosure [Line Items]
Company 401K plan contribution (percentage)		3.00%