Customer Lists and Other Identifiable Intangible Assets, Net - Reconciliation of Activity for Other Identifiable Intangible Assets (Parenthetical) (Detail) - System Transformation Transactions [Member] $ in Millions	12 Months Ended
	Dec. 31, 2017 USD ($)
Finite Lived Intangible Assets [Line Items]
Increase in acquisitions for expansion territories and expansion facilities acquired	$ 51.5
Customer Lists [Member]
Finite Lived Intangible Assets [Line Items]
Increase in acquisitions for expansion territories and expansion facilities acquired	$ 0.5