Consolidated Statements of Shareholders’ Equity - USD ($) $ in Millions	Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]
Balances at beginning of period at Sep. 30, 2013	$ 335.4	$ 0.2	$ (7.8)	$ 224.0	$ 125.4	$ (6.4)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	19.3				19.3
Other comprehensive loss	(5.2)					(5.2)
Excercise of stock options	1.3			1.3
Share-based compensation	4.3			4.3
Repurchase of stock	(9.7)		(9.7)
Repurchase of stock - adjustments to APIC				0.0
Balances at end of period at Sep. 30, 2014	345.4	0.2	(17.5)	229.6	144.7	(11.6)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	55.7				55.7
Other comprehensive loss	(5.9)					(5.9)
Excercise of stock options	3.0			3.0
Share-based compensation	3.6			3.6
Repurchase of stock	(4.7)		(4.5)
Stock held in escrow for business combination - share recapture			(4.8)
Repurchase of stock - adjustments to APIC				(0.2)
Stock held in escrow for business combination	0.0			4.8
Balances at end of period at Sep. 30, 2015	397.1	0.2	(26.8)	240.8	200.4	(17.5)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	54.7				54.7
Other comprehensive loss	(7.1)					(7.1)
Excercise of stock options	3.5			3.5
Share-based compensation	5.1			5.1
Repurchase of stock	(19.5)		(19.5)
Stock held in escrow for business combination				0.0
Balances at end of period at Sep. 30, 2016	$ 433.8	$ 0.2	$ (46.3)	$ 249.4	$ 255.1	$ (24.6)