Fair Value of Financial Instruments - Summary of Carrying Values and Fair Values of Financial Instruments (Parenthetical) (Detail) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Publicly traded retail notes traded at a premium to par	$ 67	$ 1,681

Fair value portion of liabilities pertaining to principal and customer trading transactions, or which may be incurred with the objective of generating a profit from short-term fluctuations in price as part of an entity's market-making, hedging and proprietary trading. Examples include, but are not limited to, short positions in securities, derivatives and commodities.

No definition available.

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