Quarterly Financial Summary (Unaudited) - Schedule of Quarterly Financial Summary (Parenthetical) (Detail) - USD ($) $ in Millions	3 Months Ended
Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018	Mar. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Significant legal settlements charge	$ 7.1	$ 30.0	$ 5.0	$ 6.0	$ 3.5
Non-deductible for income tax purposes		$ 23.3

Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to nondeductible expenses.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32687-109319

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32698-109319

Name:	us-gaap_IncomeTaxReconciliationNondeductibleExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration