CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Millions	Total	Common Stock	Additional Paid-in Capital	Treasury Stock, At Cost	Retained (Deficit) Earnings	Accumulated Other Comprehensive Income (Loss)
Beginning balances (in shares) at Dec. 31, 2019		37,679,000
Beginning balances at Dec. 31, 2019	$ 175.5	$ 0.4	$ 189.7	$ (20.4)	$ 2.8	$ 3.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	4.7		4.7
Issuance of restricted stock (in shares)		42,000
Issuance of restricted stock	0.0		(0.7)	0.7
Stock withheld for employee taxes (in shares)		(47,000)
Stock withheld for employee taxes	(1.4)			(1.4)
Proceeds from issuance of common stock (in shares)		221,000
Proceeds from issuance of common stock	3.3		(1.0)	4.3
Dividends	$ (134.7)				(134.7)
Purchase of treasury shares (in shares)	(392,337)	(392,000)
Purchase of treasury shares	$ (7.2)			(7.2)
Issuance of shares under employee stock purchase plan (in shares)		49,000
Issuance of shares under employee stock purchase plan	0.8		0.8
Change in cumulative translation adjustment	0.4					0.4
Net income	65.4				65.4
Ending balances (in shares) at Dec. 31, 2020		37,552,000
Ending balances at Dec. 31, 2020	106.8	$ 0.4	193.5	(24.0)	(66.5)	3.4
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	2.9		2.9
Issuance of restricted stock (in shares)		78,000
Issuance of restricted stock	0.0		(1.3)	1.3
Stock withheld for employee taxes (in shares)		(77,000)
Stock withheld for employee taxes	(3.0)			(3.0)
Proceeds from issuance of common stock (in shares)		246,000
Proceeds from issuance of common stock	4.9		(0.4)	5.3
Dividends	$ (62.3)				(62.3)
Purchase of treasury shares (in shares)	0
Issuance of shares under employee stock purchase plan (in shares)		55,000
Issuance of shares under employee stock purchase plan	$ 1.1		1.1
Change in cumulative translation adjustment	(0.1)					(0.1)
Net income	$ 103.3				103.3
Ending balances (in shares) at Dec. 31, 2021	37,854,409	37,854,000
Ending balances at Dec. 31, 2021	$ 153.6	$ 0.4	195.8	(20.4)	(25.5)	3.3
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	4.5		4.5
Issuance of restricted stock (in shares)		32,000
Issuance of restricted stock	0.0		(0.6)	0.6
Stock withheld for employee taxes (in shares)		(12,000)
Stock withheld for employee taxes	(0.4)			(0.4)
Proceeds from issuance of common stock (in shares)		34,000
Proceeds from issuance of common stock	0.8		0.1	0.7
Dividends	$ (27.4)				(27.4)
Purchase of treasury shares (in shares)	0
Issuance of shares under employee stock purchase plan (in shares)		53,000
Issuance of shares under employee stock purchase plan	$ 1.4		1.4
Change in cumulative translation adjustment	(0.9)					(0.9)
Net income	$ 78.8				78.8
Ending balances (in shares) at Dec. 31, 2022	37,960,605	37,961,000
Ending balances at Dec. 31, 2022	$ 210.4	$ 0.4	$ 201.2	$ (19.5)	$ 25.9	$ 2.4