Consolidated Statement of Changes in Stockholders' Equity - USD ($) $ in Millions	Total	Cumulative change related to the adoption of ASU 2023-02	Cumulative effect, period of adoption, adjusted balance	Common Stock Including Additional Paid in Capital [Member]	Common Stock Including Additional Paid in Capital [Member] Cumulative change related to the adoption of ASU 2023-02	Common Stock Including Additional Paid in Capital [Member] Cumulative effect, period of adoption, adjusted balance	Retained earnings	Retained earnings Cumulative change related to the adoption of ASU 2023-02	Retained earnings Cumulative effect, period of adoption, adjusted balance	Accumulated other comprehensive loss	Accumulated other comprehensive loss Cumulative change related to the adoption of ASU 2023-02	Accumulated other comprehensive loss Cumulative effect, period of adoption, adjusted balance
Equity, beginning balance at Dec. 31, 2023	$ 3,227.5	$ 1.2	$ 3,228.7	$ 2,448.9	$ 0.0	$ 2,448.9	$ 1,135.1	$ 1.2	$ 1,136.3	$ (356.5)	$ 0.0	$ (356.5)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	58.4			0.0			58.4			0.0
Other comprehensive income (loss), net of tax expense	$ (30.4)			0.0			0.0			(30.4)
Stock repurchased and retired (in shares)	43,690
Non-vested common shares issued (in shares)	685,363
Stock Issued During Period, Shares, Restricted Stock Award, Forfeited	11,676
Common stock transactions:
Common shares purchased and retired	$ (1.1)			(1.1)			0.0			0.0
Non-vested common shares issued	0.0			0.0			0.0			0.0
Non-vested common shares forfeited or canceled	0.0			0.0			0.0			0.0
Stock-based compensation expense	$ 2.9			2.9			0.0			0.0
Common dividends (in dollars per share)	$ 0.47
Common cash dividend declared	$ (48.8)			0.0			(48.8)			0.0
Equity, ending balance at Mar. 31, 2024	3,209.7			2,450.7			1,145.9			(386.9)
Equity, beginning balance at Dec. 31, 2024	3,304.0			2,459.5			1,166.4			(321.9)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	50.2			0.0			50.2			0.0
Other comprehensive income (loss), net of tax expense	$ 54.4			0.0			0.0			54.4
Stock repurchased and retired (in shares)	106,630
Non-vested common shares issued (in shares)	480,289
Stock Issued During Period, Shares, Restricted Stock Award, Forfeited	49,862
Common stock transactions:
Common shares purchased and retired	$ (3.2)			(3.2)			0.0			0.0
Non-vested common shares issued	0.0			0.0			0.0			0.0
Non-vested common shares forfeited or canceled	0.0			0.0			0.0			0.0
Stock-based compensation expense	$ 3.9			3.9			0.0			0.0
Common dividends (in dollars per share)	$ 0.47
Common cash dividend declared	$ (48.0)			0.0			(48.0)			0.0
Equity, ending balance at Mar. 31, 2025	$ 3,361.3			$ 2,460.2			$ 1,168.6			$ (267.5)