Reconciliation of Federal Income Taxes Computed at Statutory Rate with Income Taxes (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Component Of Net Income Tax Assets And Liabilities [Line Items]
Expected income tax expense (benefit) at 35%	$ 27,842	[1]	$ 4,091	[1]	$ (1,577)	[1]
Foreign tax rate differential	(2,688)		(764)		613
Taxable income (non-consolidated subsidiaries for tax)	768		946		832
Intercompany dividends	921		572		738
Research and development credit			(74)		(1,223)
State income tax expense (benefit) - net of taxes	1,147		884		(178)
Tax-exempt interest	(216)		(342)		(561)
Non-deductible expenses	5,861		2,624		2,261
Loss carrybacks	(1,442)		(1,829)
Adjustments to deferred tax liabilities	9,371		10,781		8,716
Dividends received deductions on investments	(634)		(500)		(656)
Valuation allowance	(71,106)		(7,163)		(1,146)
Other - net	537		115		256
Income tax (benefit) expense	$ (29,639)		$ 9,341		$ 8,075
Effective income tax rates (%)	(37.30%)	[1]	79.90%	[1]	(179.20%)	[1]

[1] Calculated using income (loss) before taxes and after noncontrolling interests.