Investments - Summary of Amortized Cost and Fair Value of Securities Available-For-Sale (Parenthetical) (Detail) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
U.S. government and agency securities [Member] \| Pledged securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Carrying Amount	$ 21.5	$ 20.2

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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