Debt (Narrative) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Feb. 28, 2029	Feb. 28, 2028	Aug. 08, 2026	Aug. 08, 2025	Aug. 08, 2024	Dec. 31, 2023	Dec. 09, 2022	Jul. 30, 2015
Debt Instrument [Line Items]
Document Period End Date	Mar. 31, 2024
Payments of Debt Issuance Costs	$ 0	$ 72,000
Debt issuance costs, net of amortization	(2,260,000)							$ (2,328,000)
Line of Credit Facility, Remaining Borrowing Capacity	35,000,000
Senior Notes	311,303,000							336,207,000
Letters of Credit Outstanding, Amount	9,300,000							13,500,000
2026 Notes
Debt Instrument [Line Items]
Senior Notes	75,000,000							75,000,000
2027 Notes
Debt Instrument [Line Items]
Senior Notes	37,500,000							37,500,000
2028 Notes
Debt Instrument [Line Items]
Senior Notes	100,000,000							125,000,000
2029 Notes
Debt Instrument [Line Items]
Senior Notes	100,000,000							100,000,000
Senior Notes
Debt Instrument [Line Items]
Debt issuance costs, net of amortization	(1,197,000)							(1,293,000)
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity									$ 300,000,000	$ 35,000,000
Borrowings on lines of credit	$ 0							$ 0
Forecast [Member]
Debt Instrument [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Rolling after Year Five			$ 70,000,000	$ 30	$ 50,000,000	$ 12,500,000	$ 12,500,000