Other Employee Benefit Plans Other Employee Benefit Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Compensation and Retirement Disclosure [Abstract]
401(k) matching contributions	$ 7.5	$ 6.9	$ 4.9
Pension liability	$ 2.8	$ 3.6