Disclosure of accumulated other comprehensive income (loss) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013		Dec. 31, 2013
Foreign Currency Abstract
Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax, Beginning Balance	$ (36,099)	[1]	$ (31,277)	[1]
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss), before Reclassification and Tax	(2,115)	[1]	724	[1]
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment Realized upon Sale or Liquidation, before Tax	7,718	[1]	0	[1]
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Parent, Total	5,603	[1]	724	[1]
Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax, Ending Balance	(30,496)	[1]	(30,553)	[1]
Defined Benefit Pension Plans And Defined Benefit Postretirement Plans Disclosure Abstract
Accumulated Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net of Tax, Beginning Balance	(104,302)	[1]	(225,846)	[1]
Other Comprehensive Income Loss Amortization Pension And Other Postretirement Benefit Plans Net Prior Service Cost Recognized In Net Periodic Pension Cost Net Of Tax	1,298	[1]	4,318	[1]
Other Comprehensive Income Reclassification Of Defined Benefit Plans Net Gain Loss Recognized In Net Periodic Benefit Cost Net Of Tax	(580)	[1]	0	[1]
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax, Portion Attributable to Parent, Total	718	[1]	4,318	[1]
Accumulated Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net of Tax, Ending Balance	(103,584)	[1]	(221,528)	[1]
Unrealized Gain Loss On Investments Abstract
Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax, Beginning Balance	(48,344)	[1]	154,568	[1]
Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Reclassification Adjustments	26,089	[1]	(24,006)	[1]
Other Comprehensive Income Loss Reclassification Adjustment For Sale Of Securities Included In Net Income Net Of Tax	0	[1]	0	[1]
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax, Total	26,089	[1]	(24,006)	[1]
Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax, Ending Balance	(22,255)	[1]	130,562	[1]
Unrealized net gain (losses) on Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax, Beginning Balance	0	[1]	(313)	[1]
Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period	(1,053)	[1]	(69)	[1]
Other Comprehensive Income Loss Reclassification Adjustment On Derivatives Included In Net Income Net Of Tax	1,113	[1]	(107)	[1]
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax, Portion Attributable to Parent, Total	60	[1]	(176)	[1]
Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax, Ending Balance	60	[1]	(489)	[1]
Accumulated other comprehensive income (loss)	$ (156,275)	[1]	$ (122,008)	[1]	$ (188,745)

[1] All amounts presented are net of tax.