Tax Effects of Temporary Differences That Give Rise to Federal, Foreign, State and Local Deferred Tax Assets and Deferred Tax Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Deferred tax assets:
Loss reserve discount	$ 25,353	$ 24,820
Unearned premiums	31,486	29,080
Compensation related	11,175	10,586
State and local net deferred tax assets	721	777
Other	4,315	3,732
Total gross deferred tax assets	73,050	68,995
Less: Valuation allowance	(721)	(777)
Total deferred tax assets	72,329	68,218
Deferred tax liabilities:
Net unrealized gains/ losses on securities	(13,053)	(26,730)
Deferred acquisition costs	(24,037)	(22,120)
Net unrealized foreign exchange	(4,164)	(4,470)
Other	(2,709)	(2,787)
Total deferred tax liabilities	(68,429)	(69,685)
Net deferred income tax asset	3,900
Net deferred income tax (liability)		(1,467)
Lloyd's
Deferred tax liabilities:
Lloyd's year of account deferral	$ (24,466)	$ (13,578)