Differences in Tax Provision for Financial Statement Purposes and Expected Tax Provision at Weighted Average Tax Rate (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax [Line Items]
Expected tax provision at weighted average rate	$ (1,496)	$ (6,434)	$ 3,465
Adjustments:
Non-resident withholding			6,250
Tax exempt interest	(394)	(441)	(472)
Dividend exclusion	(617)	(784)	(1,340)
Other	257	(1,064)	435
Actual taxes on continuing operations	$ (2,250)	$ (8,723)	$ 8,338
Expected tax provision at weighted average	(3.10%)	(19.60%)	4.90%
Adjustments:
Non-resident withholding			8.80%
Tax exempt interest, % of Pre-Tax Income	(0.80%)	(1.30%)	(0.70%)
Dividend exclusion, % of Pre-Tax Income	(1.30%)	(2.40%)	(1.90%)
Other, % of Pre-Tax Income	0.50%	(3.30%)	0.60%
Actual taxes on continuing operations, % of Pre-Tax Income	(4.70%)	(26.60%)	11.70%