Long-term Debt and Credit Agreement (Details)			3 Months Ended
	Feb. 19, 2020	Feb. 21, 2018 USD ($)	Mar. 31, 2020 USD ($)	Mar. 31, 2019 USD ($)	Feb. 20, 2018 USD ($)	Sep. 30, 2016 USD ($)
Long-term Debt and Credit Arrangements (Details) [Line Items]
Borrowings from line of credit			$ 133,500,000	$ 85,500,000
Letter of Credit
Long-term Debt and Credit Arrangements (Details) [Line Items]
Long-term line of credit			1,000,000.0
Revolving Credit Facility
Long-term Debt and Credit Arrangements (Details) [Line Items]
Decrease in overall borrowing costs, percentage		0.50%
Original Credit Agreement | Letter of Credit
Long-term Debt and Credit Arrangements (Details) [Line Items]
Maximum borrowing capacity						$ 25,000,000
Original Credit Agreement | Bridge Loan
Long-term Debt and Credit Arrangements (Details) [Line Items]
Maximum borrowing capacity						20,000,000
Original Credit Agreement | Revolving Credit Facility
Long-term Debt and Credit Arrangements (Details) [Line Items]
Debt instrument, aggregate principal amount						155,000,000
Original Credit Agreement | Secured Debt
Long-term Debt and Credit Arrangements (Details) [Line Items]
Debt instrument, aggregate principal amount						$ 270,000,000
Debt outstanding					$ 267,000,000
Senior Secured Revolving Credit Facility | Revolving Credit Facility
Long-term Debt and Credit Arrangements (Details) [Line Items]
Maximum borrowing capacity		$ 425,000,000
Borrowings from line of credit		$ 242,000,000	133,500,000
Debt instrument, term		5 years
Repaid amount			93,500,000
Unused borrowing capacity			$ 337,000,000
First Amended and Restated Credit Agreement
Long-term Debt and Credit Arrangements (Details) [Line Items]
Line of credit facility, accordion feature, higher borrowing capacity option		$ 175,000,000
Debt instrument, covenant, consolidated senior secured leverage ratio, maximum		1.75
Debt instrument, covenant, consolidated interest coverage ratio, minimum	3.00	3.00
Debt instrument, covenant, consolidated leverage ratio, scenario one, maximum		3.50
Debt instrument, covenant, consolidated leverage ratio, scenario two, maximum		3.25
Debt instrument, covenant, consolidated leverage ratio, scenario three, maximum		3.00
Debt instrument, covenant, consolidated leverage ratio, scenario four, maximum		2.75
First Amended and Restated Credit Agreement | Base Rate
Long-term Debt and Credit Arrangements (Details) [Line Items]
Debt instrument, basis spread on variable rate		0.75%
First Amended and Restated Credit Agreement | Eurodollar
Long-term Debt and Credit Arrangements (Details) [Line Items]
Debt instrument, basis spread on variable rate		1.75%
Commitment fee percentage		0.25%
First Amended and Restated Credit Agreement | Minimum
Long-term Debt and Credit Arrangements (Details) [Line Items]
Commitment fee percentage		0.20%
First Amended and Restated Credit Agreement | Minimum | Base Rate
Long-term Debt and Credit Arrangements (Details) [Line Items]
Debt instrument, basis spread on variable rate		0.50%
First Amended and Restated Credit Agreement | Minimum | Eurodollar
Long-term Debt and Credit Arrangements (Details) [Line Items]
Debt instrument, basis spread on variable rate		1.50%
First Amended and Restated Credit Agreement | Maximum
Long-term Debt and Credit Arrangements (Details) [Line Items]
Commitment fee percentage		0.40%
First Amended and Restated Credit Agreement | Maximum | Base Rate
Long-term Debt and Credit Arrangements (Details) [Line Items]
Debt instrument, basis spread on variable rate		1.50%
First Amended and Restated Credit Agreement | Maximum | Eurodollar
Long-term Debt and Credit Arrangements (Details) [Line Items]
Debt instrument, basis spread on variable rate		2.50%
First Amended and Restated Credit Agreement | Letter of Credit
Long-term Debt and Credit Arrangements (Details) [Line Items]
Maximum borrowing capacity		$ 40,000,000
First Amended and Restated Credit Agreement | Bridge Loan
Long-term Debt and Credit Arrangements (Details) [Line Items]
Maximum borrowing capacity		$ 40,000,000
Second Amended and Restated Credit Agreement
Long-term Debt and Credit Arrangements (Details) [Line Items]
Debt instrument, covenant, consolidated leverage ratio, scenario one, maximum	3.50
Debt instrument, covenant, consolidated leverage ratio, scenario two, maximum	4.50
Debt instrument, covenant, consolidated leverage ratio, scenario three, maximum	4.25
Debt instrument, covenant, consolidated leverage ratio, scenario four, maximum	3.50
Debt instrument, covenant, consolidated leverage ratio, scenario five, maximum	3.25
Debt instrument, covenant, consolidated leverage ratio, scenario six, maximum	3.00
Second Amended and Restated Credit Agreement | Base Rate
Long-term Debt and Credit Arrangements (Details) [Line Items]
Debt instrument, basis spread on variable rate	1.25%
Second Amended and Restated Credit Agreement | Eurodollar
Long-term Debt and Credit Arrangements (Details) [Line Items]
Debt instrument, basis spread on variable rate	2.25%
Commitment fee percentage	0.35%
Second Amended and Restated Credit Agreement | Minimum
Long-term Debt and Credit Arrangements (Details) [Line Items]
Commitment fee percentage	0.20%
Second Amended and Restated Credit Agreement | Minimum | Base Rate
Long-term Debt and Credit Arrangements (Details) [Line Items]
Debt instrument, basis spread on variable rate	0.50%
Second Amended and Restated Credit Agreement | Minimum | Eurodollar
Long-term Debt and Credit Arrangements (Details) [Line Items]
Debt instrument, basis spread on variable rate	1.50%
Second Amended and Restated Credit Agreement | Maximum
Long-term Debt and Credit Arrangements (Details) [Line Items]
Commitment fee percentage	0.50%
Second Amended and Restated Credit Agreement | Maximum | Base Rate
Long-term Debt and Credit Arrangements (Details) [Line Items]
Debt instrument, basis spread on variable rate	2.00%
Second Amended and Restated Credit Agreement | Maximum | Eurodollar
Long-term Debt and Credit Arrangements (Details) [Line Items]
Debt instrument, basis spread on variable rate	3.00%