Debt and Financing Arrangements (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Oct. 15, 2018
Other, Net
Debt Instrument [Line Items]
Payments of financing costs	$ 100,000	$ 800,000	$ 700,000	$ 2,300,000
Term Loan and Revolving Facility
Debt Instrument [Line Items]
Partial repayment of debt	23,100,000		78,000,000.0
Term Loan and Revolving Facility
Debt Instrument [Line Items]
Long-term debt	0		0
Revolving Facility
Debt Instrument [Line Items]
Long-term debt	$ 0		$ 0
Subsequent Event | Revolving Facility
Debt Instrument [Line Items]
Principal amount					$ 150,000,000
Subsequent Event | Credit Agreement
Debt Instrument [Line Items]
Additional borrowings available					100,000,000
Subsequent Event | Swing Loans
Debt Instrument [Line Items]
Additional borrowings available					20,000,000
Subsequent Event | Letter of Credit
Debt Instrument [Line Items]
Additional borrowings available					$ 20,000,000