Credit Facility (Details) - USD ($)	1 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Line of Credit Facility [Line Items]
Proceeds from credit facility		$ 35,000,000	$ 80,100,000	$ 450,400,000
Line of Credit | Revolving Credit Facility
Line of Credit Facility [Line Items]
Current borrowing capacity		300,000,000.0
Possible borrowing capacity increase		150,000,000.0
Proceeds from credit facility	$ 35,000,000.0
Long-term debt - credit facility		$ 100,000,000.0	65,000,000.0
Line of Credit | Revolving Credit Facility | Minimum
Line of Credit Facility [Line Items]
Commitment fee percentage		0.20%
Fixed charge coverage ratio		1.25
Equity securities limitation, leverage ratio		2.75
Debt instrument, covenant, availability		$ 25,000,000.0
Line of Credit | Revolving Credit Facility | Maximum
Line of Credit Facility [Line Items]
Commitment fee percentage		0.35%
Leverage ratio		3.25
Line of Credit | Letter of Credit
Line of Credit Facility [Line Items]
Current borrowing capacity		$ 10,000,000.0
Letters of credit outstanding		1,500,000	$ 3,400,000
Line of Credit | Swingline Loan
Line of Credit Facility [Line Items]
Current borrowing capacity		$ 10,000,000.0
Line of Credit | Federal Funds Effective Swap Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate		0.50%
Line of Credit | LIBOR
Line of Credit Facility [Line Items]
Basis spread on variable rate		1.00%
Line of Credit | LIBOR | Revolving Credit Facility | Minimum
Line of Credit Facility [Line Items]
Basis spread on variable rate		1.25%
Line of Credit | LIBOR | Revolving Credit Facility | Maximum
Line of Credit Facility [Line Items]
Basis spread on variable rate		1.75%
Line of Credit | Base Rate | Minimum
Line of Credit Facility [Line Items]
Basis spread on variable rate		0.25%
Line of Credit | Base Rate | Maximum
Line of Credit Facility [Line Items]
Basis spread on variable rate		0.75%