Banking Facilities and Debt (Details) $ in Thousands			12 Months Ended
	Aug. 03, 2023 USD ($)	May 07, 2015	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)
Summary of outstanding debt
Total Debt			$ 0	$ 0
Maximum
Banking facilities and other debt
Pro forma Cash Flow Leverage Ratio to be maintained to purchase, redeem or otherwise acquire shares of common stock			3
Cash flow leverage ratio		3.5
Revolving Facilities
Banking facilities and other debt
Maximum borrowing capacity	$ 75,000
Accordion feature period	4 years
Maximum borrowing capacity accordion feature	$ 50,000
Revolving Facilities | SOFR
Banking facilities and other debt
Interest rate margin (as a percent)	0.10%
Revolving Facilities | Minimum
Banking facilities and other debt
Commitment fee (as a percent)	0.225%
Revolving Facilities | Minimum | Lender's prime rate
Banking facilities and other debt
Interest rate margin (as a percent)	0.00%
Revolving Facilities | Minimum | SOFR
Banking facilities and other debt
Interest rate margin (as a percent)	1.00%
Revolving Facilities | Maximum
Banking facilities and other debt
Commitment fee (as a percent)	0.35%
Revolving Facilities | Maximum | Lender's prime rate
Banking facilities and other debt
Interest rate margin (as a percent)	1.00%
Revolving Facilities | Maximum | SOFR
Banking facilities and other debt
Interest rate margin (as a percent)	2.00%
Letter of Credit
Banking facilities and other debt
Maximum borrowing capacity	$ 10,000
Revolving Facility
Banking facilities and other debt
Letters of credit outstanding			$ 6,632