Revenue (Detail)	9 Months Ended
	Sep. 30, 2020
Revenue, Performance Obligation [Abstract]
Number of Types of Performance Obligations	2
Stand Ready Performance Obligations [Member]
Revenue, Performance Obligation [Abstract]
Revenue, Performance Obligation, Description of Good or Service	those that require us to stand ready to provide goods and services to a customer to use as and when requested (“Stand Ready Performance Obligations”)
Other Performance Obligations [Member]
Revenue, Performance Obligation [Abstract]
Revenue, Performance Obligation, Description of Good or Service	those that do not require us to stand ready (“Other Performance Obligations”)