Contingencies - Multi-employer Pension Plan (Details 2) - Multi-employer pension plan - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2015
Multi-employer pension plan
(Reduction in) addition to accrued plan liability	$ 0.4
Payroll and benefits payable
Multi-employer pension plan
Accrued plan liability	$ 0.9	$ 0.9