Subsequent Events - Additional Information (Detail) - 2017 Credit Facility - Subsequent Events $ in Millions	May 01, 2019 USD ($)
Subsequent Event [Line Items]
Percentage of fee equal to amount of outstanding loan	0.10%
Total fee amount	$ 0.2

Amount of the fee that accompanies borrowing money under the debt instrument.

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 210.5-02.22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_DebtInstrumentFeeAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant