Investments - Summary of Amortized Cost, Gross Unrealized Gains and Losses, and Estimated Fair Value of Available-for-Sale Securities (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Schedule of Available-for-sale Securities [Line Items]
Fixed-maturity securities, Cost or Amortized Cost	$ 207,983	$ 184,670
Fixed-maturity securities, Gross Unrealized Gain	3,101	338
Fixed-maturity securities, Gross Unrealized Loss	(331)	(2,285)
Fixed-maturity securities, Estimated Fair Value	210,753	182,723
Fixed-Maturity Securities [Member] \| U.S. Treasury and U.S. Government Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed-maturity securities, Cost or Amortized Cost	26,399	61,979
Fixed-maturity securities, Gross Unrealized Gain	92	24
Fixed-maturity securities, Gross Unrealized Loss	(7)	(206)
Fixed-maturity securities, Estimated Fair Value	26,484	61,797
Fixed-Maturity Securities [Member] \| Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed-maturity securities, Cost or Amortized Cost	162,725	103,580
Fixed-maturity securities, Gross Unrealized Gain	2,366	134
Fixed-maturity securities, Gross Unrealized Loss	(322)	(1,809)
Fixed-maturity securities, Estimated Fair Value	164,769	101,905
Fixed-Maturity Securities [Member] \| State, Municipalities, and Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed-maturity securities, Cost or Amortized Cost	9,995	10,567
Fixed-maturity securities, Gross Unrealized Gain	166	98
Fixed-maturity securities, Gross Unrealized Loss		(3)
Fixed-maturity securities, Estimated Fair Value	10,161	10,662
Fixed-Maturity Securities [Member] \| Exchange-Traded Debt [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed-maturity securities, Cost or Amortized Cost	8,746	8,426
Fixed-maturity securities, Gross Unrealized Gain	472	82
Fixed-maturity securities, Gross Unrealized Loss	(2)	(261)
Fixed-maturity securities, Estimated Fair Value	9,216	8,247
Fixed-Maturity Securities [Member] \| Redeemable Preferred Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed-maturity securities, Cost or Amortized Cost	118	118
Fixed-maturity securities, Gross Unrealized Gain	5
Fixed-maturity securities, Gross Unrealized Loss		(6)
Fixed-maturity securities, Estimated Fair Value	$ 123	$ 112

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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-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
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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).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Amount 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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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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