Investments - Debt Securities and Other Investments, Recorded at Fair Value (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 35,784	$ 41,042
Gross Unrealized Gains	163	27
Gross Unrealized Losses	(34)	(270)
Fair Value	35,913	40,799
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	10,733	20,777
Gross Unrealized Gains	95	19
Gross Unrealized Losses		(112)
Fair Value	10,828	20,684
Municipal Fixed-Rate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	931	1,339
Gross Unrealized Losses	(1)	(26)
Fair Value	930	1,313
Asset-Backed Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	7,222	5,230
Gross Unrealized Gains	35	5
Gross Unrealized Losses	(2)	(14)
Fair Value	7,255	5,221
Mortgage/Agency-Backed Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	7,366	3,833
Gross Unrealized Gains	29	2
Gross Unrealized Losses	(7)	(44)
Fair Value	7,388	3,791
U.S. Government Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	9,160	9,271
Gross Unrealized Gains	4	1
Gross Unrealized Losses	(21)	(66)
Fair Value	9,143	9,206
Foreign Government Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	372	592
Gross Unrealized Losses	(3)	(8)
Fair Value	$ 369	$ 584

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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