Postretirement Benefits Other Than Pensions - Schedule of Postretirement Benefit Plans (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Funded status of the plans	$ 7,217	$ 7,113
U.S. Other Postretirement Benefits [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligations at beginning of year	35,785	44,063
Service cost	422	586	542
Interest cost	1,589	1,626	1,795
Actuarial loss (gain)	2,556	(7,659)
Benefits paid	(2,624)	(2,856)
Plan change	0	0
Other	25	25	75
Foreign currency exchange rate effect	0	0
Benefit obligation at end of year	37,753	35,785	44,063
Funded status of the plans	(37,753)	(35,785)
Net amount recognized at December 31	(37,753)	(35,785)
Non-U.S. Other Postretirement Benefits [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligations at beginning of year	16,905	20,450
Service cost	545	659	650
Interest cost	752	738	822
Actuarial loss (gain)	3,533	(2,276)
Benefits paid	(668)	(659)
Plan change	0	(715)
Other	0	0	0
Foreign currency exchange rate effect	(1,580)	(1,292)
Benefit obligation at end of year	19,487	16,905	20,450
Funded status of the plans	(19,487)	(16,905)
Net amount recognized at December 31	$ (19,487)	$ (16,905)