Pension and Other Employee Benefits - Additional Information (Detail) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Pension Plan With Accumulated Benefit Obligation In Excess Of Fair Value Of Plan Assets [Line Items]
Unrecognized actuarial losses included in accumulated other comprehensive loss, net of tax		$ 3,700,000	$ 3,700,000	$ 5,700,000
Unrecognized actuarial losses included in accumulated other comprehensive loss, tax		1,000,000	$ 1,000,000	2,000,000
Defined contribution plans, maximum employee contribution			75.00%
Contribution description			The Company makes matching contributions equal to half of the first six percent of eligible compensation contributed by each employee
Percent of contribution made			6.00%
Defined benefit plan, supplementary contributions by employer			$ 4,100,000	2,800,000	$ 4,000,000
Loss on partial settlement of pension plan			1,720,000
U.S. Pension Plan 2017 [Member]
Defined Benefit Pension Plan With Accumulated Benefit Obligation In Excess Of Fair Value Of Plan Assets [Line Items]
Minimum cash contribution to pension plan			0
U.S. Pension Plan 2018 [Member]
Defined Benefit Pension Plan With Accumulated Benefit Obligation In Excess Of Fair Value Of Plan Assets [Line Items]
Minimum cash contribution to pension plan			0
U.S Pension Plan 2019 [Member]
Defined Benefit Pension Plan With Accumulated Benefit Obligation In Excess Of Fair Value Of Plan Assets [Line Items]
Minimum cash contribution to pension plan			0
U.S Pension Plan 2020 [Member]
Defined Benefit Pension Plan With Accumulated Benefit Obligation In Excess Of Fair Value Of Plan Assets [Line Items]
Minimum cash contribution to pension plan			0
U.S. Pension Plan 2021 [Member]
Defined Benefit Pension Plan With Accumulated Benefit Obligation In Excess Of Fair Value Of Plan Assets [Line Items]
Minimum cash contribution to pension plan			0
Pension Benefits [Member]
Defined Benefit Pension Plan With Accumulated Benefit Obligation In Excess Of Fair Value Of Plan Assets [Line Items]
Benefit obligation		43,075,000	43,075,000	48,844,000	33,990,000
Defined benefit plan, supplementary contributions by employer			98,000	248,000
Loss on partial settlement of pension plan			1,720,000	0
Settlement of remaining benefit obligation			7,438,000	0
Pension Benefits [Member] | Non-U.S. Plans [Member]
Defined Benefit Pension Plan With Accumulated Benefit Obligation In Excess Of Fair Value Of Plan Assets [Line Items]
Benefit obligation		24,991,000	24,991,000	23,200,000	7,802,000
Defined benefit plan, supplementary contributions by employer			98,000	248,000
Loss on partial settlement of pension plan			0	0
Settlement of remaining benefit obligation			0	0
Pension Benefits [Member] | US Plan [Member]
Defined Benefit Pension Plan With Accumulated Benefit Obligation In Excess Of Fair Value Of Plan Assets [Line Items]
Benefit obligation		18,084,000	18,084,000	25,644,000	$ 26,188,000
Defined benefit plan, supplementary contributions by employer			0	0
Loss on partial settlement of pension plan		$ 1,700,000	1,720,000	0
Settlement of remaining benefit obligation			$ 7,438,000	$ 0
Pension Benefits [Member] | US Plan [Member] | Scenario Forecast [Member]
Defined Benefit Pension Plan With Accumulated Benefit Obligation In Excess Of Fair Value Of Plan Assets [Line Items]
Benefit obligation	$ 1,300,000
Settlement of remaining benefit obligation	18,700,000
Additional settlement loss	$ 5,300,000