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, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Fixed-maturity securities, Cost or Amortized Cost	$ 167,223	$ 128,614
Equity securities, Cost or Amortized Cost	46,323	47,548
Total available-for-sale securities, Cost or Amortized Cost	213,546	176,162
Total available-for-sale securities, Gross Unrealized Gain	4,246	1,896
Total available-for-sale securities, Gross Unrealized Gain	5,487	2,139
Total available-for-sale securities, Gross Unrealized Gain	9,733	4,035
Total available-for-sale securities, Gross Unrealized Loss	(1,453)	(5,501)
Total available-for-sale securities, Gross Unrealized Loss	(350)	(1,450)
Total available-for-sale securities, Gross Unrealized Loss	(1,803)	(6,951)
Fixed-maturity securities, Estimated Fair Value	170,016	125,009
Equity securities, Estimated Fair Value	51,460	48,237
Total available-for-sale securities, Estimated Fair Value	221,476	173,246
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	430	108
Total available-for-sale securities, Gross Unrealized Gain	10	5
Fixed-maturity securities, Estimated Fair Value	440	113
Fixed-Maturity Securities [Member] | Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed-maturity securities, Cost or Amortized Cost	77,432	42,560
Total available-for-sale securities, Gross Unrealized Gain	1,007	74
Total available-for-sale securities, Gross Unrealized Loss	(1,191)	(4,815)
Fixed-maturity securities, Estimated Fair Value	77,248	37,819
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	77,040	75,812
Total available-for-sale securities, Gross Unrealized Gain	2,921	1,632
Total available-for-sale securities, Gross Unrealized Loss	(194)	(120)
Fixed-maturity securities, Estimated Fair Value	79,767	77,324
Fixed-Maturity Securities [Member] | Exchange-Traded Debt [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed-maturity securities, Cost or Amortized Cost	12,084	9,817
Total available-for-sale securities, Gross Unrealized Gain	300	177
Total available-for-sale securities, Gross Unrealized Loss	(68)	(565)
Fixed-maturity securities, Estimated Fair Value	12,316	9,429
Fixed-Maturity Securities [Member] | Redeemable Preferred Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed-maturity securities, Cost or Amortized Cost	237	317
Total available-for-sale securities, Gross Unrealized Gain	8	8
Total available-for-sale securities, Gross Unrealized Loss		(1)
Fixed-maturity securities, Estimated Fair Value	$ 245	$ 324