Summary of Changes in Benefit Obligation and Plan Assets for Defined Benefit Pension and Postretirement Benefit Plans (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Change in Plan Assets:
Plan assets at fair value, end of year	$ 475,940		$ 456,445
Net Amount Recognized in Consolidated Balance Sheets:
Noncurrent accrued benefit liability	(229,963)		(193,046)
Defined benefit pension plans
Change in Benefit Obligation:
Benefit obligation, beginning of year	616,938		669,351
Service cost	7,515		12,982		13,285
Interest cost	27,708		25,580		29,530
Impact of currency exchange rate changes	(10,673)		(2,206)
Actuarial loss (gain)	75,839		(57,418)
Benefits paid	(39,686)		(31,351)
Benefit obligation, end of year	677,641		616,938		669,351
Change in Plan Assets:
Plan assets at fair value, beginning of year	456,445		406,163
Actual return on plan assets	43,804		47,529
Employer contributions	21,596		32,078
Impact of currency exchange rate changes	(6,219)		2,026
Benefits paid	(39,686)		(31,351)
Plan assets at fair value, end of year	475,940		456,445		406,163
Net Amount Recognized in Consolidated Balance Sheets:
Funded status, end of year	(201,701)		(160,493)
Current accrued benefit liability	(2,540)		(2,661)
Noncurrent accrued benefit liability	(199,161)		(157,832)
Total accrued benefit liability	(201,701)		(160,493)
Amounts Recognized in Accumulated Other Comprehensive Loss:
Net actuarial loss	253,593		205,091
Prior service (credit)	(9,036)		(10,093)
Total amount recognized in accumulated other comprehensive loss, before tax	244,557	[1]	194,998	[1]
Postretirement benefit plans
Change in Benefit Obligation:
Benefit obligation, beginning of year	37,914		35,433
Service cost	67		82		79
Interest cost	1,377		1,585		1,411
Actuarial loss (gain)	(2,188)		4,048
Benefits paid	(2,768)		(3,234)
Benefit obligation, end of year	34,402		37,914		35,433
Change in Plan Assets:
Employer contributions	2,768		3,234
Benefits paid	(2,768)		(3,234)
Net Amount Recognized in Consolidated Balance Sheets:
Funded status, end of year	(34,402)		(37,914)
Current accrued benefit liability	(3,600)		(2,700)
Noncurrent accrued benefit liability	(30,802)		(35,214)
Total accrued benefit liability	(34,402)		(37,914)
Amounts Recognized in Accumulated Other Comprehensive Loss:
Net actuarial loss	4,914		7,119
Total amount recognized in accumulated other comprehensive loss, before tax	$ 4,914	[1]	$ 7,119	[1]

[1] Amounts exclude related tax benefits of $88.0 million and $70.2 million for December 31, 2014 and 2013, respectively, which are also included in accumulated other comprehensive loss.