Schedule of Accumulated Other Comprehensive Income, Net of Tax (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Deferred taxes	$ (352)	$ (3,896)
Accumulated other comprehensive income (loss), net of tax	(618)	4,078	$ 23,384
Fixed Maturities
Schedule of Available-for-sale Securities [Line Items]
Net unrealized gains (losses)	(1,308)	(2,184)
Common Shares
Schedule of Available-for-sale Securities [Line Items]
Net unrealized gains (losses)	$ 1,042	$ 10,158