Summary of Business Segment Information (Parenthetical) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014
Segment Reporting Information [Line Items]
Ceded premiums written	$ 94,905	[1]	$ 88,989	[1]	$ 18,072
Personal Lines Segment
Segment Reporting Information [Line Items]
Federal excise tax relating to cessions from Insurance Operations to Reinsurance Operations	1,181		1,265
Commercial Lines Segment
Segment Reporting Information [Line Items]
Federal excise tax relating to cessions from Insurance Operations to Reinsurance Operations	523		1,051		$ 1,114
American Reliable Insurance Company | Personal Lines Segment
Segment Reporting Information [Line Items]
Ceded premiums written	$ 35,334		$ 55,829
Quota share agreement percentage	100.00%		100.00%

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