Long-term Debt - Schedule of Long-term Debt (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Debt Instrument [Line Items]
Total long-term debt	$ 444,700,000		$ 444,700,000		$ 382,100,000
Amortization of debt issuance costs			600,000	$ 600,000
Revolving credit facility
Debt Instrument [Line Items]
Unamortized debt issuance costs	1,100,000		1,100,000		1,700,000
Revolving credit facility, expansion feature	200,000,000.0		200,000,000.0
Average borrowings	163,400,000	$ 371,100,000	284,200,000	295,000,000.0
Unused Credit Facility and letter of credit participation fees	400,000	300,000	1,000,000.0	900,000
Amortization of debt issuance costs	$ 200,000	$ 200,000	$ 600,000	$ 600,000
Weighted-average interest rate	1.40%	3.50%	1.90%	3.60%
Revolving credit facility
Debt Instrument [Line Items]
Total long-term debt	$ 363,000,000.0		$ 363,000,000.0		324,800,000
Outstanding letters of credit	19,400,000		19,400,000		16,700,000
Amounts available to borrow	352,100,000		352,100,000		341,700,000
Obligations under capital leases
Debt Instrument [Line Items]
Total long-term debt	81,700,000		81,700,000		$ 57,300,000
Minimum | Revolving credit facility
Debt Instrument [Line Items]
Average borrowings	69,000,000.0	$ 252,800,000	69,000,000.0	$ 141,700,000
Maximum | Revolving credit facility
Debt Instrument [Line Items]
Average borrowings	$ 401,000,000.0	$ 489,000,000.0	$ 499,300,000	$ 489,000,000.0