Changes in Benefit Obligations and Plan Assets as Well as Funded Status of Retirement Plans (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($) Investment	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Number Of Indexed Funds | Investment	6
Change in plan assets
Fair value of plan assets at beginning of year	$ 754,979
Fair value of plan assets at end of year	704,779	$ 754,979
Pension Benefits [Member]
Change in benefit obligation [Roll Forward]
Obligation at beginning of year	756,170	635,243
Service cost	15,562	13,529	$ 15,834
Interest cost	28,066	29,757	26,791
Actuarial (gains) losses	(73,890)	104,374
Liabilities assumed in acquisition	0	11,080
Plan amendments	23	0
Benefits paid	(32,316)	(30,079)
Curtailment Gain	(522)	0
Participants’ contributions	0	0
Foreign currency exchange rate changes	(7,798)	(7,734)
Obligation at end of year	685,295	756,170	635,243
Change in plan assets
Fair value of plan assets at beginning of year	754,979	691,063
Actual return on plan assets	(19,054)	83,120
Assets assumed in acquisition	0	9,631
Employer contributions	1,170	1,244
Participants’ contributions	0	0
Benefits paid	(32,316)	(30,079)
Fair value of plan assets at end of year	704,779	754,979	691,063
Funded status	19,484	(1,191)
Amounts recognized in the consolidated balance sheets
Non-current assets	79,548	76,199
Current liabilities	(1,191)	(1,298)
Non-current liabilities	(58,873)	(76,092)
Net amount recognized	19,484	(1,191)
Amounts recognized in accumulated other comprehensive loss (income)
Net actuarial loss (gain)	151,872	152,480
Prior service cost (credit)	1,377	2,391
Net amount recognized	153,249	154,871
Other Postretirement Benefits [Member]
Change in benefit obligation [Roll Forward]
Obligation at beginning of year	37,428	36,505
Service cost	444	535	682
Interest cost	1,281	1,661	1,605
Actuarial (gains) losses	(5,018)	1,438
Liabilities assumed in acquisition	0	0
Plan amendments	(3,730)	(722)
Benefits paid	(3,243)	(2,893)
Curtailment Gain	0	0
Participants’ contributions	860	904
Foreign currency exchange rate changes	0	0
Obligation at end of year	28,022	37,428	36,505
Change in plan assets
Fair value of plan assets at beginning of year	0	0
Actual return on plan assets	0	0
Assets assumed in acquisition	0	0
Employer contributions	2,383	1,989
Participants’ contributions	860	904
Benefits paid	(3,243)	(2,893)
Fair value of plan assets at end of year	0	0	$ 0
Funded status	(28,022)	(37,428)
Amounts recognized in the consolidated balance sheets
Non-current assets	0	0
Current liabilities	(2,672)	(3,094)
Non-current liabilities	(25,350)	(34,334)
Net amount recognized	(28,022)	(37,428)
Amounts recognized in accumulated other comprehensive loss (income)
Net actuarial loss (gain)	(8,027)	(3,357)
Prior service cost (credit)	(13,207)	(12,534)
Net amount recognized	$ (21,234)	$ (15,891)