Discontinued Operations - Supplemental Disclosure of Discontinued Operation (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
(Loss) income from discontinued operations, net of income taxes	$ (3.0)	$ (2.9)	$ (14.8)	$ (2.4)
LifeWorks [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net revenues		21.1	28.3	59.9
Income (loss) from operations before income taxes		0.4	(0.9)	1.9
Income tax expense	(3.0)	(2.4)	(13.9)	(3.9)
(Loss) income from discontinued operations, net of income taxes	$ (3.0)	(2.0)	(14.8)	(2.0)
Depreciation and amortization		1.0	$ 1.4	3.0
Capital expenditures				0.2
UK Business [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net revenues		0.0		0.0
Income (loss) from operations before income taxes		0.0		0.0
(Loss) gain on sale of businesses		(0.7)		(0.7)
Income tax expense		0.0		0.0
(Loss) income from discontinued operations, net of income taxes		(0.7)		(0.7)
Divested Benefits Continuation Businesses [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net revenues		0.0		0.0
Income (loss) from operations before income taxes		0.1
(Loss) gain on sale of businesses		(0.4)		0.5
Income tax expense		0.2		(0.2)
(Loss) income from discontinued operations, net of income taxes		$ (0.2)		$ 0.3