Investment Securities - Schedule of Investments in Accordance with Fair Value Measurement (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Class of securities:
Total fixed-maturity securities, Estimated Fair Value	$ 82,459	$ 99,055
Total investments fair value	87,732	106,356
Money Market Funds [Member]
Class of securities:
Money market funds	5,273	7,301
Level 1
Class of securities:
Total fixed-maturity securities, Estimated Fair Value	57,534	75,037
Total investments fair value	62,807	82,338
Level 1 | Money Market Funds [Member]
Class of securities:
Money market funds	5,273	7,301
Level 2
Class of securities:
Total fixed-maturity securities, Estimated Fair Value	24,925	24,018
Total investments fair value	24,925	24,018
U.S. Government Treasury Securities [Member]
Class of securities:
Total fixed-maturity securities, Estimated Fair Value	250	248
U.S. Government Treasury Securities [Member] | Level 1
Class of securities:
Total fixed-maturity securities, Estimated Fair Value	250	248
Obligations of U.S. Government Sponsored Enterprises [Member]
Class of securities:
Total fixed-maturity securities, Estimated Fair Value	61,441	69,382
Obligations of U.S. Government Sponsored Enterprises [Member] | Level 1
Class of securities:
Total fixed-maturity securities, Estimated Fair Value	49,985	63,909
Obligations of U.S. Government Sponsored Enterprises [Member] | Level 2
Class of securities:
Total fixed-maturity securities, Estimated Fair Value	11,456	5,473
Corporate Debt Securities [Member]
Class of securities:
Total fixed-maturity securities, Estimated Fair Value	12,948	21,061
Corporate Debt Securities [Member] | Level 1
Class of securities:
Total fixed-maturity securities, Estimated Fair Value	3,231	8,873
Corporate Debt Securities [Member] | Level 2
Class of securities:
Total fixed-maturity securities, Estimated Fair Value	9,717	12,188
Foreign Corporate Debt Securities [Member]
Class of securities:
Total fixed-maturity securities, Estimated Fair Value	7,820	8,364
Foreign Corporate Debt Securities [Member] | Level 1
Class of securities:
Total fixed-maturity securities, Estimated Fair Value	4,068	2,007
Foreign Corporate Debt Securities [Member] | Level 2
Class of securities:
Total fixed-maturity securities, Estimated Fair Value	$ 3,752	$ 6,357