Differences in Tax Provision for Financial Statement Purposes and Expected Tax Provision at Weighted Average Tax Rate (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Income Tax [Line Items]
Expected tax provision at weighted average rate	$ 933	$ (5,580)	$ (9,896)	$ (9,595)
Adjustments:
Tax exempt interest	(101)	(107)	(304)	(326)
Dividend exclusion	(3)	(175)	(480)	(588)
Other	234	(119)	268	(373)
Actual tax on continuing operations	$ 1,063	$ (5,981)	$ (10,412)	$ (10,882)
Expected tax provision at weighted average rate	8.80%	(57.40%)	(913.80%)	(292.30%)
Adjustments:
Tax exempt interest, % of Pre-Tax Income	(1.00%)	(1.10%)	(28.10%)	(9.90%)
Dividend exclusion, % of Pre-Tax Income	(0.00%)	(1.80%)	(44.30%)	(17.90%)
Other, % of Pre-Tax Income	2.20%	(1.20%)	24.80%	(11.40%)
Actual tax on continuing operations, % of Pre-Tax Income	10.00%	(61.50%)	(961.40%)	(331.50%)