CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (UNAUDITED) - USD ($) $ in Millions	Total	Common Stock	Additional Paid In Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Income
BEGINNING BALANCE (in shares) at Dec. 31, 2022		33,429,557
BEGINNING BALANCE at Dec. 31, 2022	$ 493.5	$ 0.3	$ 228.8	$ 513.1		$ 40.6
BEGINING BALANCE, Treasury Stock (in shares) at Dec. 31, 2022					(5,123,075)
BEGINING BALANCE, Treasury Stock at Dec. 31, 2022					$ (289.3)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	178.9			178.9
Issuance of common stock awards to employees (in shares)		146,354
Surrender of common stock awards (in shares)					(49,719)
Surrender of common stock awards	(5.8)				$ (5.8)
Share-based compensation expense	10.2		10.2
Share-based compensation issued to directors (in shares)		6,538
Share-based compensation issued to directors	0.5		0.5
Dividends declared	$ (53.7)			(53.7)
Common stock repurchase, inclusive of excise tax obligation (in shares)	0
Other comprehensive income (loss), net of tax	$ 4.6					4.6
ENDING BALANCE (in shares) at Sep. 30, 2023		33,582,449
ENDING BALANCE at Sep. 30, 2023	628.2	$ 0.3	239.5	638.3		45.2
ENDING BALANCE, Treasury Stock (in shares) at Sep. 30, 2023					(5,172,794)
ENDING BALANCE, Treasury Stock at Sep. 30, 2023					$ (295.1)
BEGINNING BALANCE (in shares) at Jun. 30, 2023		33,582,403
BEGINNING BALANCE at Jun. 30, 2023	560.7	$ 0.3	236.1	579.7		39.7
BEGINING BALANCE, Treasury Stock (in shares) at Jun. 30, 2023					(5,171,835)
BEGINING BALANCE, Treasury Stock at Jun. 30, 2023					$ (295.1)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	68.0			68.0
Issuance of common stock awards to employees (in shares)		46
Surrender of common stock awards (in shares)					(959)
Share-based compensation expense	3.2		3.2
Share-based compensation issued to directors	0.2		0.2
Dividends declared	$ (9.4)			(9.4)
Common stock repurchase, inclusive of excise tax obligation (in shares)	0
Other comprehensive income (loss), net of tax	$ 5.5					5.5
ENDING BALANCE (in shares) at Sep. 30, 2023		33,582,449
ENDING BALANCE at Sep. 30, 2023	$ 628.2	$ 0.3	239.5	638.3		45.2
ENDING BALANCE, Treasury Stock (in shares) at Sep. 30, 2023					(5,172,794)
ENDING BALANCE, Treasury Stock at Sep. 30, 2023					$ (295.1)
BEGINNING BALANCE (in shares) at Dec. 31, 2023	33,587,701	33,587,701
BEGINNING BALANCE at Dec. 31, 2023	$ 670.3	$ 0.3	244.7	693.8		33.7
BEGINING BALANCE, Treasury Stock (in shares) at Dec. 31, 2023	(5,220,363)				(5,220,363)
BEGINING BALANCE, Treasury Stock at Dec. 31, 2023	$ (302.2)				$ (302.2)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	189.7			189.7
Issuance of common stock awards to employees (in shares)		121,775
Surrender of common stock awards (in shares)					(36,691)
Surrender of common stock awards	(8.0)				$ (8.0)
Share-based compensation expense	11.7		11.7
Share-based compensation issued to directors (in shares)		4,186
Share-based compensation issued to directors	0.6		0.6
Dividends declared	$ (75.1)			(75.1)
Common stock repurchase, inclusive of excise tax obligation (in shares)	(315,000)				(314,864)
Common stock repurchase, inclusive of excise tax obligation	$ (66.9)				$ (66.9)
Other comprehensive income (loss), net of tax	$ (5.9)					(5.9)
ENDING BALANCE (in shares) at Sep. 30, 2024	33,713,662	33,713,662
ENDING BALANCE at Sep. 30, 2024	$ 716.4	$ 0.3	257.0	808.4		27.8
ENDING BALANCE, Treasury Stock (in shares) at Sep. 30, 2024	(5,571,918)				(5,571,918)
ENDING BALANCE, Treasury Stock at Sep. 30, 2024	$ (377.1)				$ (377.1)
BEGINNING BALANCE (in shares) at Jun. 30, 2024		33,706,380
BEGINNING BALANCE at Jun. 30, 2024	685.3	$ 0.3	252.9	749.6		38.4
BEGINING BALANCE, Treasury Stock (in shares) at Jun. 30, 2024					(5,471,918)
BEGINING BALANCE, Treasury Stock at Jun. 30, 2024					$ (355.9)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	68.6			68.6
Issuance of common stock awards to employees (in shares)		7,282
Share-based compensation expense	3.9		3.9
Share-based compensation issued to directors (in shares)
Share-based compensation issued to directors	0.2		0.2
Dividends declared	$ (9.8)			(9.8)
Common stock repurchase, inclusive of excise tax obligation (in shares)	(100,000)				(100,000)
Common stock repurchase, inclusive of excise tax obligation	$ (21.2)				$ (21.2)
Other comprehensive income (loss), net of tax	$ (10.6)					(10.6)
ENDING BALANCE (in shares) at Sep. 30, 2024	33,713,662	33,713,662
ENDING BALANCE at Sep. 30, 2024	$ 716.4	$ 0.3	$ 257.0	$ 808.4		$ 27.8
ENDING BALANCE, Treasury Stock (in shares) at Sep. 30, 2024	(5,571,918)				(5,571,918)
ENDING BALANCE, Treasury Stock at Sep. 30, 2024	$ (377.1)				$ (377.1)