Retirement Benefits - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014 Investment	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax	$ 14,027,000	$ (4,580,000)	$ (3,309,000)
Accumulated benefit obligation, pension benefit plans	720,200,000	606,100,000
Multi employer pension plan contributions	6,282,000	6,162,000	6,398,000
Defined contribution plans contributions charged to expense	9,000,000	7,800,000	7,600,000
Target Allocation	100.00%
Plan assets held under management by single investment company	98.00%
Number of commingled debt and equity index funds	6
Number of asset funds	3
Voluntary contributions to Domestic Pension Benefit Plans			76,000,000
United States
Defined Benefit Plan Disclosure [Line Items]
Equity securities, target allocation as percentage of total equity securities	85.00%
Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Target Allocation	58.00%
Equity Securities | United States
Defined Benefit Plan Disclosure [Line Items]
Target Allocation	49.00%
Debt securities
Defined Benefit Plan Disclosure [Line Items]
Target Allocation	42.00%
Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Multi Employer Funded Status	65.00%
Foreign Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligations in excess of plan assets, projected benefit obligation	77,400,000	61,100,000
Accumulated benefit obligations in excess of plan assets, accumulated benefit obligation	$ 71,100,000	$ 56,500,000
Benefit obligation discount rate	2.00%	3.70%
Benefit obligation rate of compensation increase	3.50%	3.50%
Net periodic benefit cost discount rate	3.70%	3.60%	4.90%
Net periodic benefit cost rate of compensation increase	3.50%	3.50%	3.50%