Investments - Summary of Amortized Cost, Gross Unrealized Gains and Losses, and Estimated Fair Value of Available-for-Sale Securities (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	$ 98,743	$ 110,738
Equity securities, Gross Unrealized Gain	3,160	2,862
Equity securities, Cost or Amortized Cost	38,856	17,248
Equity securities, Gross Unrealized Loss	(1,485)	(1,048)
Total available-for-sale securities, Cost or Amortized Cost	137,599	127,986
Debt securities	100,177	112,151
Equity securities, Estimated Fair Value	39,097	17,649
Total available-for-sale securities	139,274	129,800
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Equity securities, Gross Unrealized Gain	1,444	920
Equity securities, Cost or Amortized Cost	38,856	17,248
Equity securities, Gross Unrealized Loss	(1,203)	(519)
Equity securities, Estimated Fair Value	39,097	17,649
Fixed-Maturity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	98,743	110,738
Equity securities, Gross Unrealized Gain	1,716	1,942
Equity securities, Gross Unrealized Loss	(282)	(529)
Debt securities	100,177	112,151
Fixed-Maturity Securities [Member] | U.S. Treasury and U.S. Government Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	1,330	4,549
Equity securities, Gross Unrealized Gain	34	37
Equity securities, Gross Unrealized Loss		(22)
Debt securities	1,364	4,564
Fixed-Maturity Securities [Member] | Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	17,020	25,139
Equity securities, Gross Unrealized Gain	16	484
Equity securities, Gross Unrealized Loss	(157)	(219)
Debt securities	16,879	25,404
Fixed-Maturity Securities [Member] | Commercial Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	11,163	10,929
Equity securities, Gross Unrealized Gain	408	499
Equity securities, Gross Unrealized Loss	(40)	(96)
Debt securities	11,531	11,332
Fixed-Maturity Securities [Member] | State, Municipalities, and Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	59,796	69,715
Equity securities, Gross Unrealized Gain	1,158	917
Equity securities, Gross Unrealized Loss	(41)	(181)
Debt securities	60,913	70,451
Fixed-Maturity Securities [Member] | Redeemable Preferred Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	9,434	406
Equity securities, Gross Unrealized Gain	100	5
Equity securities, Gross Unrealized Loss	(44)	(11)
Debt securities	$ 9,490	$ 400