Debt and Equity Securities (Net Unrealized Gains (Losses) (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Schedule Of Available For Sale Securities [Line Items]
Debt securities for which an OTTI has been recognized	$ (137)	$ (625)
Available-for-sale Securities, Gross unrealized gains (losses)	15,133	(4,833)
Debt Securities-All Other
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Gross unrealized gains (losses)	(9,834)	(28,152)
Equity Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Gross unrealized gains (losses)	$ 25,104	$ 23,944