Accumulated Other Comprehensive Income (Loss) (Components of Accumulated Other Comprehensive Income (Loss) (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Statement Of Income And Comprehensive Income [Abstract]
Net unrealized gains (losses) on securities, Beginning Balance	$ 21,938	$ (13,409)	$ (3,237)
Net unrealized gains (losses) on securities, Pretax change Before reclassifications	(44,205)	122,243	(746)
Net unrealized gains (losses) on securities, Pretax change in other-than-temporary impairments for which credit-related portion was recognized in earnings	3,809	6,502	3,573
Net unrealized gain (losses) Amounts reclassified from accumulated other comprehensive income	(9,795)	(69,834)	(10,987)
Net unrealized gains (losses) on securities, Tax effect	19,526	(23,564)	(2,012)
Net unrealized gains (losses) on securities, Ending Balance	(8,727)	21,938	(13,409)
Foreign currency translation adjustment, Beginning Balance	9,924	4,793	10,960
Foreign currency translation adjustment, Pretax change before reclassifications	(13,650)	5,131	(6,167)
Foreign currency translation adjustment, Ending Balance	(3,726)	9,924	4,793
Pension benefit adjustment, Beginning Balance	(182,408)	(168,837)	(156,803)
Pension benefit adjustment, Pretax change	53,080	(46,602)	(42,721)
Pension benefit adjustment,Amounts reclassified from accumulated other comprehensive income	27,648	23,983	22,662
Pension benefit adjustment, Tax effect	(31,404)	9,048	8,025
Pension benefit adjustment, Ending Balance	(133,084)	(182,408)	(168,837)
Accumulated other comprehensive income (loss), Beginning Balance	(150,546)	(177,453)	(149,080)
Accumulated other comprehensive income (loss), Pretax change	(4,775)	80,772	(49,634)
Accumulated other comprehensive income (loss), Pretax change in other-than-temporary impairments for which credit-related portion was recognized in earnings	3,809	6,502	3,573
Accumulated other comprehensive income (loss), Amounts reclassified from accumulated other comprehensive income	17,853	(45,851)	11,675
Accumulated other comprehensive income (loss), Tax effect	(11,878)	(14,516)	6,013
Accumulated other comprehensive income (loss), Ending Balance	$ (145,537)	$ (150,546)	$ (177,453)