Consolidated Statement of Changes in Stockholders' Equity - USD ($) $ in Millions	Total	Common stock	Retained earnings	Accumulated other comprehensive loss
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	121.9	0.0	121.9	0.0
Other comprehensive income (loss), net of tax expense	$ 89.0	0.0	0.0	89.0
Stock repurchased and retired (in shares)	107,648
Non-vested common shares issued (in shares)	515,641
Stock Issued During Period, Shares, Restricted Stock Award, Forfeited	119,780
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	$ 7.2	7.2	0.0	0.0
Common dividends (in dollars per share)	$ 0.94
Common cash dividend declared	$ (97.1)	0.0	(97.1)	0.0
Equity, ending balance at Jun. 30, 2025	3,421.8	2,463.5	1,191.2	(232.9)
Equity, beginning balance at Mar. 31, 2025	3,361.3	2,460.2	1,168.6	(267.5)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	71.7	0.0	71.7	0.0
Other comprehensive income (loss), net of tax expense	$ 34.6	0.0	0.0	34.6
Stock repurchased and retired (in shares)	1,018
Non-vested common shares issued (in shares)	35,352
Stock Issued During Period, Shares, Restricted Stock Award, Forfeited	69,918
Common stock transactions:
Common shares purchased and retired	$ 0.0	0.0	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	$ 3.3	3.3	0.0	0.0
Common dividends (in dollars per share)	$ 0.47
Common cash dividend declared	$ (49.1)	0.0	(49.1)	0.0
Equity, ending balance at Jun. 30, 2025	3,421.8	2,463.5	1,191.2	(232.9)
Equity, beginning balance at Dec. 31, 2025	3,447.0	2,350.9	1,274.2	(178.1)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	144.1	0.0	144.1	0.0
Other comprehensive income (loss), net of tax expense	$ (25.4)	0.0	0.0	(25.4)
Stock repurchased and retired (in shares)	4,412,976
Non-vested common shares issued (in shares)	415,154
Stock Issued During Period, Shares, Restricted Stock Award, Forfeited	197,185
Common stock transactions:
Common shares purchased and retired	$ (157.2)	(157.2)	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	$ 5.8	5.8	0.0	0.0
Common dividends (in dollars per share)	$ 0.94
Common cash dividend declared	$ (91.7)	0.0	(91.7)	0.0
Equity, ending balance at Jun. 30, 2026	3,322.6	2,199.5	1,326.6	(203.5)
Equity, beginning balance at Mar. 31, 2026	3,358.5	2,265.5	1,288.7	(195.7)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	83.9	0.0	83.9	0.0
Other comprehensive income (loss), net of tax expense	$ (7.8)	0.0	0.0	(7.8)
Stock repurchased and retired (in shares)	1,935,883
Non-vested common shares issued (in shares)	80,943
Stock Issued During Period, Shares, Restricted Stock Award, Forfeited	54,412
Common stock transactions:
Common shares purchased and retired	$ (69.5)	(69.5)	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	$ 3.5	3.5	0.0	0.0
Common dividends (in dollars per share)	$ 0.47
Common cash dividend declared	$ (46.0)	0.0	(46.0)	0.0
Equity, ending balance at Jun. 30, 2026	$ 3,322.6	$ 2,199.5	$ 1,326.6	$ (203.5)