Fair Value of Financial Instruments - Summary Of Company Financial Instruments Carried At Fair Value In The Consolidated Balance Sheets (Detail) $ in Thousands	Dec. 31, 2018 USD ($)
Mortgage-backed Securities Available-for-sale, Fair Value Disclosure	$ 1,987
Fair Value, Inputs, Level 2 [Member]
Mortgage-backed Securities Available-for-sale, Fair Value Disclosure	$ 1,987

Fair value of securitized, pay-through debt securities collateralized by real estate mortgage loans classified as available-for-sale.

No definition available.

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