Changes in Benefit Obligations and Plan Assets as Well as Funded Status of Retirement Plans (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Change in plan assets
Fair value of plan assets at end of year	$ 691,063	$ 633,261
Pension Benefits [Member]
Change in benefit obligation [Roll Forward]
Obligation at beginning of year	672,372	609,738
Service cost	15,834	14,788	13,857
Interest cost	26,791	27,363	28,519
Actuarial (gains) losses	(54,746)	49,067
Plan amendments	1,521	(1,269)
Benefits paid	(29,071)	(28,301)
Participants’ contributions	0	0
Foreign currency exchange rate changes	2,542	986
Obligation at end of year	635,243	672,372	609,738
Change in plan assets
Fair value of plan assets at beginning of year	633,261	509,877
Actual return on plan assets	85,809	74,774
Employer contributions	1,064	76,911
Participants’ contributions	0	0
Benefits paid	(29,071)	(28,301)
Fair value of plan assets at end of year	691,063	633,261	509,877
Funded status	55,820	(39,111)
Amounts recognized in the consolidated balance sheets
Non-current assets	116,888	25,548
Current liabilities	(1,241)	(1,061)
Non-current liabilities	(59,827)	(63,598)
Net amount recognized	55,820	(39,111)
Amounts recognized in accumulated other comprehensive loss (income)
Net actuarial loss (gain)	75,539	175,763
Prior service cost (credit)	3,578	3,843
Net amount recognized	79,117	179,606
Other Postretirement Benefits [Member]
Change in benefit obligation [Roll Forward]
Obligation at beginning of year	49,177	51,131
Service cost	682	830	862
Interest cost	1,605	2,051	2,441
Actuarial (gains) losses	(10,352)	(1,299)
Plan amendments	(1,790)	(504)
Benefits paid	(3,714)	(3,904)
Participants’ contributions	897	872
Foreign currency exchange rate changes	0	0
Obligation at end of year	36,505	49,177	51,131
Change in plan assets
Fair value of plan assets at beginning of year	0	0
Actual return on plan assets	0	0
Employer contributions	2,817	3,032
Participants’ contributions	897	872
Benefits paid	(3,714)	(3,904)
Fair value of plan assets at end of year	0	0	0
Funded status	(36,505)	(49,177)
Amounts recognized in the consolidated balance sheets
Non-current assets	0	0
Current liabilities	(3,291)	(3,941)
Non-current liabilities	(33,214)	(45,236)
Net amount recognized	(36,505)	(49,177)
Amounts recognized in accumulated other comprehensive loss (income)
Net actuarial loss (gain)	(5,124)	4,994
Prior service cost (credit)	(14,682)	(15,576)
Net amount recognized	$ (19,806)	$ (10,582)