Investments (Gross Unrealized Gains and Losses by Investment Category) (Details) - USD ($) $ in Thousands	Dec. 26, 2020	Mar. 28, 2020
Available-for-Sale Securities by Investment Category
Amortized Cost	$ 16,482	$ 14,660
Gross Unrealized Gains	211	208
Gross Unrealized Losses	(20)	(94)
Available-for-sale debt securities	16,673	14,774
Residential mortgage-backed securities
Available-for-Sale Securities by Investment Category
Amortized Cost	5,209	5,400
Gross Unrealized Gains	45	69
Gross Unrealized Losses	(17)	(26)
Available-for-sale debt securities	5,237	5,443
State and political subdivision debt securities
Available-for-Sale Securities by Investment Category
Amortized Cost	6,156	4,239
Gross Unrealized Gains	151	134
Gross Unrealized Losses	(1)	(3)
Available-for-sale debt securities	6,306	4,370
Corporate debt securities
Available-for-Sale Securities by Investment Category
Amortized Cost	5,117	5,021
Gross Unrealized Gains	15	5
Gross Unrealized Losses	(2)	(65)
Available-for-sale debt securities	$ 5,130	$ 4,961

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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