Statement of Consolidated Stockholders' Equity - USD ($) $ in Millions	Total	Common Stock	Additional Paid in Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Loss
Stockholders' Equity [Roll Forward]
Net income	$ 26.3
Repurchase of common stock, shares	(83,265)
Repurchase of common stock	$ (6.4)
Ending balance at Mar. 31, 2016						$ (30.8)
Beginning balance, shares (Scenario, Previously Reported) at Dec. 31, 2016		17,651,461
Beginning balance, shares at Dec. 31, 2016	17,651,461
Beginning balance (Scenario, Previously Reported) at Dec. 31, 2016	$ 804.7	$ 0.2	$ 1,047.4	$ 75.2	$ (281.4)	(36.7)
Beginning balance at Dec. 31, 2016	804.7
Stockholders' Equity [Roll Forward]
Net income	36.0			36.0
Other comprehensive income, net of tax	1.3					1.3
Issuance of common shares to employees upon option exercises and vesting of restricted stock units and performance shares, shares		102,403
Issuance of common shares to employees upon vesting of restricted stock units and performance shares			0.0
Cancellation of shares to cover employees' tax withholdings upon vesting of non-vested shares		(55,888)
Cancellation of shares to cover employees' tax withholdings upon vesting of non-vested shares	$ (4.4)		(4.4)
Repurchase of common stock, shares	(415,346)	(415,346)
Repurchase of common stock	$ (32.7)				(32.7)
Dividends, Cash	9.3			9.3
Amortization of unearned equity compensation	$ 3.0		3.0
Ending balance, shares at Mar. 31, 2017	17,282,630	17,282,630
Ending balance at Mar. 31, 2017	$ 798.6	$ 0.2	$ 1,046.0	$ 101.9	$ (314.1)	$ (35.4)