Pension and Other Postretirement Benefits - Schedule of Changes in Projected Benefit Obligations (PBO) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Change in projected benefit obligations:
Plan settlements		$ (2,739)
Defined Benefit Pension Plan [Member] | U.S. Defined Benefit Pension Plans [Member] | U.S. [Member]
Change in projected benefit obligations:
PBO, beginning balance	$ 244,440	181,803
Åkers acquisition – PBO at March 3	0	68,081
Service cost	1,651	1,714	$ 2,743
Interest cost	8,413	9,977	7,990
Plan amendments	0	0
Plan settlements	0	(2,739)
Plan curtailments	0	(1,181)
Foreign currency exchange rate changes	0	0
Actuarial loss (gain)	13,825	(160)
Participant contributions	0	0
Benefits paid from plan assets	(12,950)	(12,679)
Benefits paid by the Corporation	(403)	(376)
PBO, Ending balance	254,976	244,440	181,803
Defined Benefit Pension Plan [Member] | Foreign Pension Benefits [Member]
Change in projected benefit obligations:
PBO, beginning balance	66,910	63,750
Åkers acquisition – PBO at March 3	0	5,393
Service cost	150	314	0
Interest cost	1,845	2,250	2,394
Plan amendments	0	0
Plan settlements	0	0
Plan curtailments	0	0
Foreign currency exchange rate changes	5,948	(11,477)
Actuarial loss (gain)	(7,954)	8,869
Participant contributions	0	0
Benefits paid from plan assets	(1,813)	(2,189)
Benefits paid by the Corporation	(473)	0
PBO, Ending balance	64,613	66,910	63,750
Other Postretirement Benefit Plans [Member]
Change in projected benefit obligations:
PBO, beginning balance	19,059	8,117
Åkers acquisition – PBO at March 3	0	17,467
Service cost	492	504	384
Interest cost	571	722	474
Plan amendments	165	(4,762)
Plan settlements	0	0
Plan curtailments	0	0
Foreign currency exchange rate changes	0	0
Actuarial loss (gain)	(2,170)	(1,598)
Participant contributions	92	80
Benefits paid from plan assets	0	0
Benefits paid by the Corporation	(1,230)	(1,471)
PBO, Ending balance	$ 16,979	$ 19,059	$ 8,117