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Investments - Contractual Maturities of Debt Securities (Detail) - USD ($) $ in Thousands | Dec. 31, 2021 | Dec. 31, 2020 | Jan. 01, 2020
--- | --- | --- | ---
Schedule of Available-for-sale Securities [Line Items] |  |  |
Available-for-sale debt securities, Fair Value/Carrying Value | $ 30,066 | $ 45,116 | $ 37,700
Corporate Bonds [Member] |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |
Less than one year | 681 |  |
One to two years | 4,902 |  |
Two to three years | 4,333 |  |
Three to five years | 831 |  |
Available-for-sale debt securities, Fair Value/Carrying Value | 10,747 | 11,885 |
Municipal Fixed-Rate Bonds [Member] |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |
Less than one year | 150 |  |
One to two years | 1,018 |  |
Two to three years | 265 |  |
Three to five years | 118 |  |
Available-for-sale debt securities, Fair Value/Carrying Value | 1,551 | 2,884 |
Asset-Backed Bonds [Member] |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |
Two to three years | 29 |  |
More than ten years | 293 |  |
Available-for-sale debt securities, Fair Value/Carrying Value | 322 | 6,708 |
Mortgage/Agency-Backed Bonds [Member] |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |
Less than one year | 801 |  |
One to two years | 868 |  |
Three to five years | 324 |  |
Five to ten years | 1,125 |  |
More than ten years | 1,618 |  |
Available-for-sale debt securities, Fair Value/Carrying Value | 4,736 | 11,644 |
U.S. Government Bonds [Member] |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |
Less than one year | 1,884 |  |
One to two years | 5,320 |  |
Two to three years | 4,421 |  |
Three to five years | 546 |  |
Available-for-sale debt securities, Fair Value/Carrying Value | 12,171 | 9,875 |
Foreign Government Bonds [Member] |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |
One to two years | 245 |  |
Two to three years | 294 |  |
Available-for-sale debt securities, Fair Value/Carrying Value | $ 539 | $ 1,337 |

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