Pre- and Post-Modification Recorded Investment Balances for Finance Receivables Modified by Portfolio Class (Parenthetical) (Detail)	3 Months Ended
Jun. 30, 2019 USD ($)
Receivables [Abstract]
Pre-Modification Recorded Investment	$ 0
Post-Modification Recorded Investment	$ 0

Post-modification amount of investment in financing receivables modified by troubled debt restructurings.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953676-111524

Name:	us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration