Effect of Reinsurance on Premiums Written and Earned (Parenthetical) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015		Dec. 31, 2014	Dec. 31, 2013
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Ceded written premiums	$ 88,989	[1]	$ 18,072	$ 18,739
Ceded earned premiums	92,852	[1]	$ 18,547	$ 19,485
American Bankers Insurance Company
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Ceded written premiums	55,800
Ceded earned premiums	$ 59,500

[1] Includes ceded written premiums and ceded earned premiums of $55.8 million and $59.5 million, respectively, to American Bankers Insurance Company.