Debt and Equity Securities (Net Unrealized Gains (Losses) (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Schedule Of Available For Sale Securities [Line Items]
Debt securities for which an OTTI has been recognized	$ 87	$ (625)
Available-for-sale Securities, Gross unrealized gains (losses)	38,111	(4,833)
Debt Securities-All Other
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Gross unrealized gains (losses)	10,408	(28,152)
Equity Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Gross unrealized gains (losses)	$ 27,616	$ 23,944