Supplementary Information for Property Casualty Underwriters (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]
Deferred Policy Acquisition Costs	$ 56,517	$ 25,238	$ 22,177
Reserves for Unpaid Claims and Claim Adjustment Expenses	680,047	675,472	779,466
Discount If Any Deducted	3,000	4,000	6,000
Unearned Premiums	286,285	120,815	116,629
Earned Premiums	504,143	268,519	248,722
Net Investment Income	34,609	28,821	37,209
Claims and Claim Adjustment Expense Incurred Related To Current Year	310,066	153,994	140,873
Claims and Claim Adjustment Expense Incurred Related To Prior Year	(34,698)	(16,433)	(7,882)
Amortization Of Deferred Policy Acquisition Costs	86,170	57,051	53,787
Paid Claims and Claim Adjustment Expenses	332,417	172,265	184,564
Premiums Written	$ 501,244	$ 273,181	$ 271,984