Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Millions	Total		Common Stock [Member]	Additional paid-in capital [Member]	Accumulated other comprehensive loss [Member]		Retained earnings (accumulated deficit) [Member]
Beginning Balance at Jun. 30, 2018	$ 966.1	[1]	$ 0.7	$ 915.4	$ (4.1)	[1]	$ 54.1	[1]
Issuance of common stock under share-based compensation plans	1.9			1.9
Issuance of common stock for acquisition	127.4			127.4
Share-based payment expense	7.7			7.7
Net income (loss)	(0.7)						(0.7)
Other comprehensive income, net of tax	(0.2)				(0.2)
Ending Balance at Sep. 30, 2018	1,102.2		0.7	1,052.4	(4.3)		53.4
Beginning Balance at Jun. 30, 2018	966.1	[1]	0.7	915.4	(4.1)	[1]	54.1	[1]
Net income (loss)	1.9
Ending Balance at Dec. 31, 2018	1,064.2		0.7	1,045.6	(5.0)		22.9
Beginning Balance at Sep. 30, 2018	1,102.2		0.7	1,052.4	(4.3)		53.4
Issuance of common stock under share-based compensation plans	2.6			2.6
Share-based payment expense	7.5			7.5
Repurchase and retirement of common stock	(50.0)			(16.9)			(33.1)
Net income (loss)	2.6						2.6
Other comprehensive income, net of tax	(0.7)				(0.7)
Ending Balance at Dec. 31, 2018	$ 1,064.2		$ 0.7	$ 1,045.6	$ (5.0)		$ 22.9

[1] Amounts adjusted due to the adoption of Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers (Topic 606). See Note 1 to the financial statements contained in Part I, Item 1 of this report for additional information.