Leases (Narrative) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Lessee, Lease, Description [Line Items]
Lease income, lessor arrangements	$ 2.1	$ 3.0
Minimum
Lessee, Lease, Description [Line Items]
Lease term	5 years
Renewal term	1 year
Maximum
Lessee, Lease, Description [Line Items]
Lease term	10 years
Renewal term	10 years