Description of Business and Basis of Presentation - Additional Information (Detail) $ in Millions	6 Months Ended
	Jun. 30, 2019 USD ($)	Jan. 01, 2019 USD ($)	Jun. 30, 2018 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of Reportable Segments	2
Operating Lease, Right-of-Use Asset	$ 476.8
Operating Lease, Liability, Noncurrent	510.2
Accounting Standards Update 2016-02 (Lease) [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating Lease, Right-of-Use Asset		$ 518.0
Operating Lease, Liability, Noncurrent		622.0
Deferred Tax Assets		150.0
Deferred Tax Liabilities		$ 125.0
Accounting Standards Update 2016-02 (Lease) [Member] | Retained Earnings [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Effect of adoption adjustment Reduction to retained earnings			$ 2.3
Accounting Standards Update 2018-02 [Member] | Retained Earnings [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Effect of adoption adjustment Reduction to retained earnings	$ 19.8