Condensed Consolidated Statement of Shareholders' Equity (Unaudited) - USD ($) shares in Thousands, $ in Millions	Total	Common Stock	Additional Paid-in Capital	Treasury Stock	Retained Earnings	Accumulated Other Comprehensive Income
Beginning Balance (in shares) at Dec. 31, 2017		37,094
Beginning Balance at Dec. 31, 2017	$ 211.8	$ 0.4	$ 186.5	$ (21.8)	$ 44.8	$ 1.9
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	0.4		0.4
Issuance of restricted stock (in shares)		38
Issuance of restricted stock	0.0		(0.5)	0.5
Stock withheld for employee taxes (in shares)		(31)
Stock withheld for employee taxes	(0.9)		(0.5)	(0.4)
Proceeds from issuance of common stock (in shares)		72
Proceeds from issuance of common stock	0.8		(0.1)	0.9
Dividends declared	(4.1)				(4.1)
Change in cumulative translation adjustment	1.4					1.4
Net income	14.6				14.6
Ending Balance (in shares) at Mar. 31, 2018		37,173
Ending Balance at Mar. 31, 2018	224.0	$ 0.4	185.8	(20.8)	55.3	3.3
Beginning Balance (in shares) at Dec. 31, 2017		37,094
Beginning Balance at Dec. 31, 2017	211.8	$ 0.4	186.5	(21.8)	44.8	1.9
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	32.8
Ending Balance (in shares) at Jun. 30, 2018		37,192
Ending Balance at Jun. 30, 2018	197.3	$ 0.4	185.7	(20.6)	32.2	(0.4)
Beginning Balance (in shares) at Mar. 31, 2018		37,173
Beginning Balance at Mar. 31, 2018	224.0	$ 0.4	185.8	(20.8)	55.3	3.3
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	0.4		0.4
Issuance of restricted stock (in shares)		19
Issuance of restricted stock	0.0		(0.2)	0.2
Stock withheld for employee taxes (in shares)		(10)
Stock withheld for employee taxes	(0.4)		(0.3)	(0.1)
Proceeds from issuance of common stock (in shares)		10
Proceeds from issuance of common stock	0.1			0.1
Dividends declared	(41.3)				(41.3)
Change in cumulative translation adjustment	(3.7)					(3.7)
Net income	18.2				18.2
Ending Balance (in shares) at Jun. 30, 2018		37,192
Ending Balance at Jun. 30, 2018	197.3	$ 0.4	185.7	(20.6)	32.2	(0.4)
Beginning Balance (in shares) at Dec. 31, 2018		37,335
Beginning Balance at Dec. 31, 2018	137.7	$ 0.4	187.0	(25.1)	(27.6)	3.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	1.5		1.5
Issuance of restricted stock (in shares)		103
Issuance of restricted stock	0.0		(1.8)	1.8
Stock withheld for employee taxes (in shares)		(34)
Stock withheld for employee taxes	(0.8)			(0.8)
Proceeds from issuance of common stock (in shares)		3
Proceeds from issuance of common stock	0.0
Issuance of shares under employee stock purchase plan (in shares)		21
Issuance of shares under employee stock purchase plan	0.4		0.4
Dividends declared	(4.5)				(4.5)
Change in cumulative translation adjustment	0.0					0.0
Net income	9.7				9.7
Ending Balance (in shares) at Mar. 31, 2019		37,428
Ending Balance at Mar. 31, 2019	144.0	$ 0.4	187.1	(24.1)	(22.4)	3.0
Beginning Balance (in shares) at Dec. 31, 2018		37,335
Beginning Balance at Dec. 31, 2018	137.7	$ 0.4	187.0	(25.1)	(27.6)	3.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	24.3
Ending Balance (in shares) at Jun. 30, 2019		37,486
Ending Balance at Jun. 30, 2019	156.1	$ 0.4	188.1	(23.2)	(12.3)	3.1
Beginning Balance (in shares) at Mar. 31, 2019		37,428
Beginning Balance at Mar. 31, 2019	144.0	$ 0.4	187.1	(24.1)	(22.4)	3.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	1.3		1.3
Issuance of restricted stock (in shares)		6
Issuance of restricted stock	0.0
Stock withheld for employee taxes (in shares)		(1)
Stock withheld for employee taxes	0.0
Proceeds from issuance of common stock (in shares)		53
Proceeds from issuance of common stock	0.6		(0.3)	0.9
Dividends declared	(4.5)				(4.5)
Change in cumulative translation adjustment	0.1					0.1
Net income	14.6				14.6
Ending Balance (in shares) at Jun. 30, 2019		37,486
Ending Balance at Jun. 30, 2019	$ 156.1	$ 0.4	$ 188.1	$ (23.2)	$ (12.3)	$ 3.1