Period between issuance and maturity of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Recent Accounting Standards - Additional Information (Detail) - USD ($)	Mar. 31, 2020	Jan. 01, 2020
Minimum \| US Treasury Securities
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Available-for-sale securities maturity range	3 months
Maximum \| US Treasury Securities
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Available-for-sale securities maturity range	1 year
ASU 2016-13
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Cumulative-effect adjustment to retained earnings		$ 0