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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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Debt and Credit Facilities - Narrative (Details) - USD ($)				3 Months Ended		6 Months Ended
	Oct. 23, 2025	Oct. 20, 2025	Jun. 10, 2025	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025	Nov. 15, 2024	Jun. 23, 2022
Line of Credit Facility [Line Items]
Line of credit facility, outstanding				$ 787,552,000		$ 787,552,000
Interest expense				4,762,000	$ 4,729,000	9,538,000	$ 10,331,000
Unsecured Debt \| Facility
Line of Credit Facility [Line Items]
Face amount			$ 150,000,000						$ 150,000,000
Amortization of debt issuance costs				100,000	$ 100,000	100,000	$ 100,000
Line of Credit \| Uncommitted Secured Letter Of Credit Facility \| Letter of Credit
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity								$ 250,000,000
Line of Credit \| Unsecured Facility
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity			$ 450,000,000
Line of credit facility, outstanding				$ 0		$ 0
Unused commitment fee percentage			0.175%
Line of Credit \| Unsecured Facility \| Letter of Credit
Line of Credit Facility [Line Items]
Stated interest rate			1.25%
Line of Credit \| Unsecured Facility \| Revolving Credit Facility
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity			$ 150,000,000
Line of Credit \| Unsecured Facility \| Revolving Credit Facility \| Prime Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate			0.50%
Line of Credit \| Unsecured Facility \| Revolving Credit Facility \| Secured Overnight Financing Rate (SOFR)
Line of Credit Facility [Line Items]
Basis spread on variable rate			1.50%
Line of Credit \| UBS Letter of Credit Facility \| Letter of Credit
Line of Credit Facility [Line Items]
Commitment fee percentage	1.40%
Line of Credit \| UBS Letter of Credit Facility \| Letter of Credit \| Minimum
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity	$ 25,000,000
Line of Credit \| UBS Letter of Credit Facility \| Letter of Credit \| Maximum
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity	$ 75,000,000
Line of Credit \| Unsecured Facility, Lloyd's \| Letter of Credit
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity		$ 260,000,000
Commitment fee percentage		1.50%