Investment Securities - Schedule of Amortized Cost, Gross Unrealized Gains, Gross Unrealized Losses and Estimated Fair Values of Fixed-Maturity Securities (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total fixed-maturity securities, Amortized Cost	$ 107,188	$ 60,202
Total fixed-maturity securities, Gross Unrealized Gains	212	590
Total fixed-maturity securities, Gross Unrealized Losses	(56)	(151)
Total fixed-maturity securities, Estimated Fair Value	107,344	60,641
Less total unrestricted fixed-maturity securities, Amortized Cost	68,046	7,895
Less total unrestricted fixed-maturity securities, Gross Unrealized Gains	60	179
Less total unrestricted fixed-maturity securities, Gross Unrealized Losses	(3)	(11)
Less total unrestricted fixed-maturity securities, Estimated Fair Value	68,103	8,063
Total fixed-maturity securities held in trust, Amortized Cost	39,142	52,307
Total fixed-maturity securities held in trust, Gross Unrealized Gains	152	411
Total fixed-maturity securities held in trust, Gross Unrealized Losses	(53)	(140)
Total fixed-maturity securities held in trust, Estimated Fair Value	39,241	52,578
Obligations of U.S. Government Sponsored Enterprises [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total fixed-maturity securities, Amortized Cost	70,483	6,491
Total fixed-maturity securities, Gross Unrealized Gains	9	12
Total fixed-maturity securities, Gross Unrealized Losses	(9)	(28)
Total fixed-maturity securities, Estimated Fair Value	70,483	6,475
Corporate Debt Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total fixed-maturity securities, Amortized Cost	25,564	41,018
Total fixed-maturity securities, Gross Unrealized Gains	171	531
Total fixed-maturity securities, Gross Unrealized Losses	(35)	(65)
Total fixed-maturity securities, Estimated Fair Value	25,700	41,484
Foreign Corporate Debt Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total fixed-maturity securities, Amortized Cost	11,141	12,693
Total fixed-maturity securities, Gross Unrealized Gains	32	47
Total fixed-maturity securities, Gross Unrealized Losses	(12)	(58)
Total fixed-maturity securities, Estimated Fair Value	$ 11,161	$ 12,682