CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY - USD ($) $ in Millions		Total	Preferred Stock and Additional Paid-in Capital	Common Stock	Additional Paid-In Capital	Treasury Shares	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Beginning Balance at Dec. 31, 2022		$ 1,232.9	$ 144.0	$ 46.4	$ 1,395.4	$ (455.1)	$ 407.3	$ (305.1)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		(78.5)					(78.5)
Other comprehensive (loss) income - change in fair value of fixed maturities, net of taxes		22.0						22.0
Other comprehensive income, net of tax		1.8						1.8
Activity under stock incentive plans		0.5		0.1	0.4
Retirement of common stock (tax payments on equity compensation)		(0.9)			(0.9)
Employee stock purchase plan		1.2			1.2
Dividends on preferred stock and Series A Preferred stock		(7.9)					(7.9)
Cash dividend declared - common stock		0.2					0.2
Ending Balance at Sep. 30, 2023		1,171.3	144.0	46.5	1,396.1	(455.1)	321.1	(281.3)
Beginning Balance at Jun. 30, 2023		1,234.8	144.0	46.5	1,395.1	(455.1)	370.6	(266.3)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		(46.9)					(46.9)
Other comprehensive (loss) income - change in fair value of fixed maturities, net of taxes		(15.5)						(15.5)
Other comprehensive income, net of tax		0.5						0.5
Activity under stock incentive plans		0.7			0.7
Retirement of common stock (tax payments on equity compensation)		(0.1)			(0.1)
Employee stock purchase plan		0.4			0.4
Dividends on preferred stock and Series A Preferred stock		(2.6)					(2.6)
Ending Balance at Sep. 30, 2023		1,171.3	144.0	46.5	1,396.1	(455.1)	321.1	(281.3)
Beginning Balance at Dec. 31, 2023		1,297.5	137.1	1,056.6	51.1	0.0	0.9	51.8
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		(94.0)					(94.0)
Other comprehensive (loss) income - change in fair value of fixed maturities, net of taxes		16.5						16.5
Other comprehensive income, net of tax		0.3						0.3
Purchase accounting adjustments	[1]	(15.3)			(15.3)
Changes in common stock due to merger with AGIH Merger Sub, Inc.	[2]	0.0		(1,256.6)	1,256.6
Dividends on preferred stock and Series A Preferred stock		(7.9)					(7.9)
Issuance of common stock		200.0		200.0
Ending Balance at Sep. 30, 2024		1,397.1	137.1	0.0	1,292.4	0.0	(101.0)	68.6
Beginning Balance at Jun. 30, 2024		1,505.6	137.1	1,256.6	51.1	0.0	33.9	26.9
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		(132.3)					(132.3)
Other comprehensive (loss) income - change in fair value of fixed maturities, net of taxes		41.3						41.3
Other comprehensive income, net of tax		0.4						0.4
Purchase accounting adjustments	[3]	(15.3)			(15.3)
Changes in common stock due to merger with AGIH Merger Sub, Inc.	[4]	0.0		(1,256.6)	1,256.6
Dividends on preferred stock and Series A Preferred stock		(2.6)					(2.6)
Ending Balance at Sep. 30, 2024		$ 1,397.1	$ 137.1	$ 0.0	$ 1,292.4	$ 0.0	$ (101.0)	$ 68.6

[1] (2) Refer to the Merger with AGIH Merger Sub, Inc. in Note 1, “Business and Significant Accounting Policies” for additional information.

[2] (1) Impact of measurement period adjustment on bargain purchase in connection with the Merger. Refer to Note 1, “Business and Significant Accounting Policies” for additional information.

[3] (1) Impact of measurement period adjustment on bargain purchase in connection with the Merger. Refer to Note 1, “Business and Significant Accounting Policies” for additional information.

[4] (2) Refer to the Merger with AGIH Merger Sub, Inc. in Note 1, “Business and Significant Accounting Policies” for additional information.