Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Long-Term Debt (2018 Revolving Credit Agreement) (Detail) - Revolving Credit Facility - USD ($)	Dec. 31, 2020	Mar. 06, 2020	Dec. 31, 2019	Aug. 17, 2018
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 100,000,000.0		$ 50,000,000.0
Letters of credit outstanding amount	$ 65,100,000		$ 2,900,000