Adoption of Revenue Guidance (Narrative) (Detail)	6 Months Ended
	Jun. 30, 2018
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Performance obligation contract original term	The performance obligation is part of a contract that has an original duration of one year or less
Expected term of delivery of product or service and customer payment	The Company expects the period between delivery of the product or service and customer payment to be one year or less.
Maximum
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Remaining contract term	3 years