Employee Retirement Plans (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Components of Net Retirement Cost
Service cost	$ 0.1	$ 0.2	$ 0.3	$ 0.4
Interest	5.0	5.1	15.0	15.1
Expected return on plan assets	(7.6)	(7.8)	(22.8)	(23.2)
Amortization of actuarial loss	1.3	1.0	3.9	1.6
Defined benefit expense	(1.2)	(1.5)	(3.6)	(6.1)
Profit sharing	4.5	3.9	14.9	12.8
Multiemployer plan	0.6	0.3	1.7	0.3
Net retirement cost	$ 3.9	$ 2.7	$ 13.0	$ 7.0