Employee Benefit Plans and Insurance (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017 USD ($) $ / employees	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Defined Contribution Plan, Employer Discretionary Contribution Amount | $	$ 3.1	$ 0.3	$ 4.2
Self Insurance Program, Major Medical and Hospitialization, Liability per Employee or Dependent per Year, Maximum	200,000
Employee-related Liabilities, Health Insurance, Self-insurance Program, Current | $	$ 2.0	2.0
Self Insurance Program, Workers' Compensation Coverage per Incident, Maximum	500,000
Self Insurance Program, General Liability Insurance, Deductible per Occurrence	250,000
Self Insurance Program, Auto Liability Insurance, Deductible per Occurrence	250,000
Accrued Insurance Premiums and Deductibles, Self Insurance Program, Workers' Compensation, General and Auto Liability Insurance | $	$ 4.6	$ 4.4