Notes payable - Additional Information (Details)	1 Months Ended
	Nov. 30, 2021 USD ($) d	Oct. 31, 2021 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Debt Instrument [Line Items]
Other notes payable			$ 160,000	$ 2,398,000
Notes payable, other than banks
Debt Instrument [Line Items]
Other notes payable			$ 200,000	$ 2,300,000
Senior Notes | 3.6% Senior Notes
Debt Instrument [Line Items]
Aggregate principal amount	$ 450,000,000
Stated interest rate (as a percent)	3.60%		3.60%
Debt issuance costs	$ 444,000,000
Senior Notes | 3.6% Senior Notes | At any time prior to August 15, 2031
Debt Instrument [Line Items]
Redemption notice period | d	15
Senior Notes | 3.6% Senior Notes | Minimum | At any time prior to August 15, 2031
Debt Instrument [Line Items]
Redemption price percentage	100.00%
Line of credit | Revolving Credit Facility
Debt Instrument [Line Items]
Remaining borrowing capacity			$ 197,500,000
Line of credit | Letter of credit
Debt Instrument [Line Items]
Remaining borrowing capacity			$ 2,500,000
Line of credit | New Credit Agreement
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 200,000,000
Line of credit | New Credit Agreement | Revolving Credit Facility
Debt Instrument [Line Items]
Increase limit		$ 125,000,000
Line of credit | New Credit Agreement | Minimum
Debt Instrument [Line Items]
Commitment fee (percent)		0.15%
Line of credit | New Credit Agreement | Minimum | Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate, line of credit (percent)		0.25%
Line of credit | New Credit Agreement | Minimum | Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Basis spread on variable rate, line of credit (percent)		1.25%
Line of credit | New Credit Agreement | Maximum
Debt Instrument [Line Items]
Commitment fee (percent)		0.30%
Line of credit | New Credit Agreement | Maximum | Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate, line of credit (percent)		0.625%
Line of credit | New Credit Agreement | Maximum | Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Basis spread on variable rate, line of credit (percent)		1.625%
Line of credit | Term Loan
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 400,000,000
Debt instrument, term		364 days