Debt (Details) - USD ($)	1 Months Ended	3 Months Ended	12 Months Ended
	Jul. 31, 2022	Sep. 30, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Debt Instrument [Line Items]
Loss on debt extinguishment			$ 0	$ 40,199,000	$ 36,914,000
Interest paid			$ 35,100,000	53,700,000	71,700,000
Convertible Junior Subordinated Debentures, at 9% per annum, Due 2063
Debt Instrument [Line Items]
Stated interest rate (in hundredths)			9.00%
Extinguishment of debt		$ 21,100,000		89,100,000	98,600,000
Conversion rate (in shares per $1,000 note)		77.9620
Principal amount of notes used in determining conversion rate		$ 1,000
Repayments of long-term debt		28,600,000		121,200,000	135,500,000
Adjustments To Additional Paid In Capital, Conversion of Convertible Debt		$ 5,300,000
Loss on debt extinguishment				$ 32,100,000	$ 36,900,000
Reduction in potentially dilutive shares due to debt extinguishment		1,600,000		6,800,000	7,500,000
Federal Home Loan Bank Advances (FHLB)
Debt Instrument [Line Items]
Loss on debt extinguishment				$ 1,300,000
Federal Home Loan Bank Advance prepayment amount				$ 156,300,000
Senior Notes | 5.75% Senior Notes due 2023
Debt Instrument [Line Items]
Stated interest rate (in hundredths)	5.75%
Loss on debt extinguishment	$ 6,800,000
Purchase of senior notes	$ 248,400,000
Senior Notes | 5.75% Senior Notes due 2023 | US Treasury (UST) Interest Rate
Debt Instrument [Line Items]
Basis spread on variable rate	0.50%
Senior Notes | 5.25% Senior Notes due 2028
Debt Instrument [Line Items]
Stated interest rate (in hundredths)			5.25%
Debt instrument, face amount			$ 650,000,000
Ownership percentage threshold for declaration of due and payable			25.00%
Senior Notes | 5.25% Senior Notes due 2028 | Debt Instrument, Redemption, Period Two
Debt Instrument [Line Items]
Redemption price, percentage (in hundredths)			102.625%
Senior Notes | 5.25% Senior Notes due 2028 | Debt Instrument, Redemption, Period Three
Debt Instrument [Line Items]
Redemption price, percentage (in hundredths)			101.313%
Senior Notes | 5.25% Senior Notes due 2028 | Debt Instrument, Redemption, Period Four
Debt Instrument [Line Items]
Redemption price, percentage (in hundredths)			100.00%