Accumulated Other Comprehensive Income (Loss) (AOCI) (Components of Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss) including non-controlling interest, Beginning Balance			$ (239,000)
Change in unrealized gains (losses) on securities			83,390
Change in foreign currency translation adjustment			3,066
Amortization of net actuarial loss			21,153
Amortization of prior service cost			(3,633)
Tax effect	$ (3,399)	$ 2,266	(38,004)	$ 833
Accumulated other comprehensive income (loss) including non-controlling interest, Ending Balance	(173,028)		(173,028)
Accumulated other comprehensive loss	(173,052)		(173,052)		$ (239,003)
Allocated to noncontrolling interests	24		24
Unrealized Gains (Losses) on Securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss) including non-controlling interest, Beginning Balance			(16,401)
Change in unrealized gains (losses) on securities			83,390
Tax effect	(1,169)	4,780	(31,303)	9,047
Accumulated other comprehensive income (loss) including non-controlling interest, Ending Balance	35,686		35,686
Accumulated other comprehensive loss	35,662		35,662
Allocated to noncontrolling interests	24		24
Foreign Currency Translation Adjustment
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss) including non-controlling interest, Beginning Balance			(57,242)
Change in foreign currency translation adjustment			3,066
Accumulated other comprehensive income (loss) including non-controlling interest, Ending Balance	(54,176)		(54,176)
Accumulated other comprehensive loss	(54,176)		(54,176)
Pension Benefit Adjustment
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss) including non-controlling interest, Beginning Balance			(165,357)
Amortization of net actuarial loss			21,153
Amortization of prior service cost			(3,633)
Tax effect	(2,230)	$ (2,514)	(6,701)	$ (8,214)
Accumulated other comprehensive income (loss) including non-controlling interest, Ending Balance	(154,538)		(154,538)
Accumulated other comprehensive loss	$ (154,538)		$ (154,538)