Pension and Other Postretirement Benefits - Net Periodic Pension and Other Postretirement Benefit Costs (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
U.S. Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 3,683	$ 4,424	$ 3,943
Interest cost	8,762	8,070	8,514
Expected return on plan assets	(10,747)	(9,368)	(9,556)
Amortization of prior service cost	854	640	668
Amortization of actuarial loss	4,183	7,146	6,087
Net cost	6,735	10,912	9,656
Foreign Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	0
Interest cost	2,695	2,551	2,506
Expected return on plan assets	(3,157)	(2,485)	(2,101)
Amortization of prior service cost	0	0	0
Amortization of actuarial loss	599	687	598
Net cost	137	753	1,003
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	505	943	804
Interest cost	688	926	919
Expected return on plan assets	0	0	0
Amortization of prior service cost	(441)	85	85
Amortization of actuarial loss	104	241	71
Net cost	$ 856	$ 2,195	$ 1,879