Investment Securities - Schedule of Amortized Cost, Gross Unrealized Gains, Gross Unrealized Losses and Estimated Fair Values of Fixed-Maturity Securities (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total fixed-maturity securities, Amortized Cost	$ 98,028	$ 99,088
Total fixed-maturity securities, Gross Unrealized Gains	126	78
Total fixed-maturity securities, Gross Unrealized Losses	(28)	(111)
Total fixed-maturity securities, Estimated Fair Value	98,126	99,055
Unrestricted Fixed-Maturity Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total fixed-maturity securities, Amortized Cost	66,522	66,481
Total fixed-maturity securities, Gross Unrealized Gains	21	14
Total fixed-maturity securities, Gross Unrealized Losses	(2)	(11)
Total fixed-maturity securities, Estimated Fair Value	66,541	66,484	[1]
Fixed-Maturity Securities Held in Trust [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total fixed-maturity securities, Amortized Cost	31,506	32,607
Total fixed-maturity securities, Gross Unrealized Gains	105	64
Total fixed-maturity securities, Gross Unrealized Losses	(26)	(100)
Total fixed-maturity securities, Estimated Fair Value	31,585	32,571	[1]
U.S. Government Treasury Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total fixed-maturity securities, Amortized Cost	249	249
Total fixed-maturity securities, Gross Unrealized Gains	1
Total fixed-maturity securities, Gross Unrealized Losses		(1)
Total fixed-maturity securities, Estimated Fair Value	250	248
Obligations of U.S. Government Sponsored Enterprises [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total fixed-maturity securities, Amortized Cost	68,453	69,392
Total fixed-maturity securities, Gross Unrealized Gains	21	13
Total fixed-maturity securities, Gross Unrealized Losses	(1)	(23)
Total fixed-maturity securities, Estimated Fair Value	68,473	69,382
Corporate Debt Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total fixed-maturity securities, Amortized Cost	20,946	21,048
Total fixed-maturity securities, Gross Unrealized Gains	93	62
Total fixed-maturity securities, Gross Unrealized Losses	(10)	(49)
Total fixed-maturity securities, Estimated Fair Value	21,029	21,061
Foreign Corporate Debt Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total fixed-maturity securities, Amortized Cost	8,380	8,399
Total fixed-maturity securities, Gross Unrealized Gains	11	3
Total fixed-maturity securities, Gross Unrealized Losses	(17)	(38)
Total fixed-maturity securities, Estimated Fair Value	$ 8,374	$ 8,364

[1] Balances derived from audited financial statements as of December 31, 2015.