Short-Term Borrowings, Long-Term Debt, and Interest Expense - Additional Information (Details) - USD ($)	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Debt Instrument [Line Items]
Total leverage ratio	3.50
Interest coverage ratio	3.00
Outstanding borrowings as floating rate debt	$ 190,000,000.0
Effect of one percentage point increase to interest expense	1,900,000
Interest paid	11,500,000	$ 10,400,000
Line of Credit
Debt Instrument [Line Items]
Letters of credit outstanding	500,000
Revolving Credit Facility | Line of Credit
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	450,000,000.0
Line of credit facility, additional borrowing capacity	150,000,000.0		$ 150,000,000.0
Line of credit facility, maximum borrowing capacity including higher borrowing capacity option	600,000,000.0
Amount outstanding under line of credit	340,000,000.0
Line of credit facility, remaining borrowing capacity	$ 109,500,000
Weighted average interest rate	4.40%
Letter of Credit | Line of Credit
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	$ 20,000,000.0
Bridge Loan | Line of Credit
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	$ 20,000,000.0
Interest Rate Swap
Debt Instrument [Line Items]
Interest rate swap, fixed rate to maturity obligation interest rate			2.677%